Hi Justin,
The key to a fine English fowler, if that is your intention, is to have it thick in the breech, taper rapidly to the wedding band or transition (if it has one), and then taper slowly to the muzzle. Rice's Griffin profile barrel with a 1.125" wide breech might be a good option. Their French fowler with 1.25" breech might also work but it does not taper enough from the breech for my preference. The Dolep barrels are too skinny in the breech. However, Jason is making one for Maria with a larger breech. My shop should be getting it soon and I will post a description for you when it arrives.
dave