Dense and fine grained sphericals (ball-type) powders are definitely beneficial to progressive loading. They will help ensure charge-weight uniformity. This is determined by a powders "Bulk Density."
One excellent powder for target grade accuracy with the ability to reproduce factory level velocity in both 9 X 19mm and the .40 S&W is Ramshot True Blue. It is also one of the most pressure stable pistol powders you can use: another benefit. True Blue has a bulk density rating of 935 grams/liter, or .935 grams/CC. You may see it listed either way. Bulk density doesn't necessarily have to be extremely high. As an example, another very good powder for both would be Ramshot Silhouette that is larger in physical size than True Blue (not large in comparison to many other powders) and it has a bulk density of 800 grams/liter, or .800 grams/CC. That is still dense enough to meter uniformly in progressive loading. Another very popular powder for both is Winchester Super Field or WSF and there are several other good choices like Vihta Vouri 3N37, N340 & N350 which can also be bought as Vectan Ba 7 1/2 from Graf & Sons.
These powders that are all slower burning than Unique give very good case fill that will help identify a charge in the case, or in the case of single-stage loading, a double-charge will overflow the case. So they have an advantage in performance as well as safety.
I'm not partial to flake powders because they tend to be the largest in physical size with lower bulk densities than Spherical or fine cut extruded powders like those from Vihta Vouri and Vectan Ba 7 1/2 that I mentioned.
Here's something I typically recommend. Go to the Hodgdon website and download the burn rate chart. Start with V-V N330 and go down to say Hodgdon Longshot. There are also 2 very fine grained and dense sphericals from Accurate that are even slightly more dense then True Blue. AA#7 does very well in 9 X 19mm with bullets 124 grs. and heavier. Not quite so good in .40 S&W. AA#5 is close in burn rate to True Blue, but without the same level of pressure stability and uniformity. Both are brands of Western Powder Co., but True Blue has a far wider range of loading possibilities than AA#5. In fact, it is possible to load every handgun cartridge from .32 ACP up to the .454 Casull with True Blue. Don't let its flexibility confuse you, it can often be the most accurate powder used and 9 X 19mm and the .40 S&W are very good examples. It's also a very good powder for full power JHP defense loads in .45 ACP where I also use it as well as for short barrel .357 Magnum loads.
With the powder availability problems we have, you might want to copy that range of powders from the burn rate chart and see what's actually available. 2 more recent powders that I haven't tried are AutoComp and CFE Pistol. AutoComp is designed to give greater muzzle pressure to better work pistols with compensators and that generally tends to mean muzzle flash which is why I haven't used it. CFE Pistol is chemically treated to reduce muzzle flash as Silhouette is, making both good candidates for defense loads if you make your own.
Just curious: have you read a couple of loading manuals? If not, buy some and read them. You'll find load data in them. This will help you find data for powders that you can find.
Even if someone gives you their pet load, you still have to determine the starting load and work up to the pet load.
9x19: 124gn JHP and 6.0gn Power Pistol. Good 9x19 powders include AA5, Power Pistol, BE86, Auto-Comp, Silhouette, AA7, and True Blue.
.40S&W: Sorry, all I shoot are 145-175gn L-SWC bullets and you probably don't want to go there. Best powders have been AA5 and Silhouette.
9mm 115gr FMJ, Titegroup 4.2 to 4.6gr produces an easy shooting load, Power Pistol 6.2 for velocity
40S&W 165 FMJ, Titegroup 4.6-5.0 is a nice range, Power Pistol or True Blue in the 7.4gr range for velocity
I have over 20 different loading manuals and I can't stress enough how important it is to rely on printed load data. The Lyman 49 manual is conservative and their loads will keep you out of trouble. You have first class loading equipment. Don't scrimp on a $20 manual!
I'd like to help you out but I constantly transpose numbers so I make it a personal rule to NOT post load data. It would be easy for a guy like me to post 6.4 grains of pistol powder when I should have posted 4.6 grains. That's typical of obtaining load data from the Internet. I rely on published load data ONLY!
In my limited reloading experience, I find it is best to use your brain. I've got manuals from Speer, Hornady etc. but they rarely have exactly what I'm looking for - then I get on the powder websites like Hodgdon and make a best guess at the middle of the road load. I started out too light and made a bunch of 9mm's that were marginal on cycling different pistols. Added a few 10ths of a grain and they worked well. I think you'll have to play with a specific powder to figure out what works for you. I apologize for being that vague. If you asked me about 115 grain 9mm plated bullets with Titegroup & a taper crimp I'd tell you that 4.4 grains of powder works great.
I despise 40 cals but as far as 9mm loads... I use exclusively titegroup. My go to plinking load is 4.1gr under a 124gr plated bullet. Eventually I'm gonna batch out some sub-sonic loads. For those I plan on using 3.4gr under a 147gr pill. My 4.1 gr load works at COLS from 1.100 to 1.160 in about 10 different 9mm handguns. Sometimes I have to seat them shorter if I am using a square tipped bullet like a hollow point or a Hornady HAP bullet.
A couple of years ago me and a few other guys on the site were running our g19s side by side through some drills. Mag dumps, some rapid fire at moving targets,etc. My gun was the only one that didn't have any malfunctions using my handloads. The other 2 guys had issues with 2 major brands in their pistols. Definitely not hating on glock, just happy with the performance of my pet load.
Ive got a whole stack of manuals. If I had it to do over again Id use the powder manufacturers website and buy quickload. Much more versatile and would've been cheaper. I use HP38 almost exclusively due to it being good for 9 and 45.
I only use data from published sources and Internet powder company loads count as published data from my perspective. They take great care in preparation of that data but always caution that variations in technique or components may change the performance. They always say....work up to the load using your techniques and components. Simply put, they advise you not to trust their data 100%.
That is how I do things. As always, you may do as you wish.