Brought up shooting 12 ga and slugs for deer, thought me early to kneel at the shooting bench.
Keep your back straight, and rock with the recoil!
Straight stocks with WIDE pads are your friend.
My first BP rifle was a TC Hawken.......[skinny curved plates are not your friend]..............my second was more like an English Sporter...........even before I had ever seen a picture of one, I understood the design.
2.1/2"s of drop, wide plate..................and a trigger guard that doesn't smack the middle finger. :'(Them Jaeger folks have that figured out
..........when your fingers all fit all in a row, and not behind the guard, it feels much better.
The ole 7ga smooth bore with 180ff and a 1000 grain ball shoot about 1100 fps.......10.5 pounds of gun, and you get a nice big push, from standing or kneeling, it's all in the stock design...........up the load to 240+ grains an.............it just KICKS..............UP and Back!!, but no bruises or marks, can't imagine what a skinny plate with a lot of drop would feel like, or do to the ole body!
I have shot my .73 cal barrel [28"] in both a 7 and 8 pound rifles, and cannot tell the difference in shooting 125ff-175ff and a 550 grain balls.
I have back down in caliber as I get older, my next rifle barrel is only a .690 bore 1.1/8 x 1.0 x 29"s.
Bruce