What a wonderful path ahead of you. I too have a Henry brass Big Boy in .45 colt. Sidearm wise, since .45 colt is my very favorite caliber..........Two S&W 25-5s (pinned barrel), Ruger flat top new model Blackhawk (Lipsey's), Cimarron P model, and the king of them all, Colt SAA 7 1/2" second gen.
The 25-5s are my hunting sidearm while toting a rifle. Those have a lot of haters because some had over size chamber mouths, mine will group 3-4" at 25 yards everyday all day. Acceptable to me from their 4" barrels. I believe 6+", are best for hunting. A perfect barrel length for an N-frame, IMHO is 4-5".