Doing things like this is why you are so well revered and respected in the SASS community Yul. You are a treasure. Thank you for making a permanent mark in our history.
165 GR 45 Colt with 25grs of FFG with filler is a soft shooting load. Cut the 10ga down to 2 3/4" using 1oz shot over 65-75 grs of FFG and yer all set with your current gear.
20ga kicks harder than a 12 because of the light weight. If the Mighty 10 is too heavy, use a 12 ga. 60-65grs FFG under 1oz of shot.
In Orygon Territory they call it a Hydrological Event when the atmospheric river melts the snow because it's a warm rain. I guess they are trying to sound smart.
I've never shot in an age based group and don't ever plan too. I shoot FCGF with cap guns, I use a Chaparral 1873 in 38WCF, and a hammer double because I like to make smoke.