Thanks for the input, but strictly looking at .410 or 28.I was recently pricing 20ga for a Christmas gift for my daughter. There are several side by side and O/U available for <$300 and ammo is (probably) more available than for the 410 or 28. If you are looking for pump or semi-auto then 12ga is the solution but what I find to be in stock are the high end $1500 and up (I wonder why those are still on the shelf?)
The problem with fourten is that it is an expert’s gun. The 1/2 ounce payload is a deterrent to success.
Most of the small kids I see on the sporting clays course are shooting 20 gauge gas guns.
^^^This.another factor to consider,
the lighter the firearm, the more felt recoil results
I would go the 20 ga and use lower velocity shotshells to reduce recoil, the extra weight and larger surface area of the butt plate on the 20a ga will absorb 95% of the recoil difference
less costly ammo allows more practice for the dollar