RE: barrel length?
I like the longer barrel simply because i feel that it have a chance to burn the powder longer and also give the bullet a chance to be a little more stable. I have 32" barrels on two of my muzzleloaders and a 33 1/2" barrel on the other. The shorter barrels like i have on my bobcat, 24" is nice in thick brush, but i dont hunt in the thick stuff so i prefer the longer barrel for open area, long distance shots.
In my deer creek manual it states that it takes a 32" barrel to completely burn 110 grains "weighed" powder.