Vader, some suggestions....
The Archives here have tons of stuff, including comparing 2 3/4 and 3" loads, handling kick and so on. Use the Search feature and be ready for truckloads of info. This is THE place to go for shotgun info.
Also, if you're shooting in an enclosed space, use BOTH plugs and muffs.Trust me on this, it'll help settle you in.
If all the deer I've shot deadernH*ll with dinky little 2 3/4" slugs, including the old 7/8 oz, 1250 FPS jobs were lined up end to end, they'd reach from here to Clarksville. All 3" slugs do that the shorter ones don't is give you a flinch faster and go through your money.
For practice, and familiarization, use generic field loads, preferably the 1 oz Lites.
Finally, I use a wearable recoil pad, the PAST for bench work with anything kicking harder than a 22 Hornet. It's a little binding for wingshooting, but I never feel kick there anyway.
HTH....