dave has good advice,take what you read here and GO TRY the feel of gun.
if you do a lot of walking, shorter lighter gun is good.
if you sit like me, i like no less than a 28 inch barrel and LONGER barrels balance a lot better than shorter ones.
back in 1970 i knew nothing about a muzzleloader.
no one helped you at all, i tried about 6 different muzzleloaders,when i got to THOMPSON HAWKINS .50 CAL FLINTLOCK,i noticed a big diffference in way it pulled up and how it felt looking at mount on wall.
i went back over all guns again, same thing, the smaller length barrels felt terrible to pull up and aim.
yes, they were light but felt terrible.
so, i bought the hawkins for 119 dollars new,back then they threw in a can of 2f powder which was 3.85 a can and rb for 1.99 for 100.
personelly, i would buy nothing but THOMPSON in the flintlock as that is where i have knowledge.
their service is great, i sent my barrel in to have nicks touched up and they fixed and blued it nice.
that was over 35 years old on gun, now THAT SERVICE.