A few years ago I rebarreled a C. Sharps Hi wall with a GM Sharps #1 taper.
Chambered to 44/90 st. (2.4"case),cut to 32" with the long Kelly front & Kelly mid range rear and Mva scope blocks,it was under 12#.
As it was it shoot extremely well,but a little to muzzle heavy.
I cut it back to 28" and added lead to the butt to bring it up to just under 12#.
I called Green Mountain a while back asking about the 3.5 taper. They have none in stock and have none on their to do list.
Should have ordered more of them when they were available.

Thnx Lots
Bob