BIG, Sounds to me like you are Good To Go! A good saddle! That was my tough issue. My old saddle would flat out give me extreme pain in my back and legs. It was well used when I bought it. It was set up with a double cinch, breast collar and britchin' strap, fer hill climbin'. It worked but was very uncomfortable on a long ride!
Gave all my tack away, after I sold my Mule!
An over-the-shoulder scabbard for the carbine will allow both hands free! GOOD idea!
Not sure I would be comfortable with the resolver in a saddle holster. As long as that works for you? Thats what counts!
GregH