I'd pick a Shiloh over a C. Sharps any time, based on my experience with them. As for options, if you want to shoot at far targets I'd recommend a pistol grip stock with little drop and a shotgun butt plate. Long Range Express, #1, or the newer Rough Rider stock. I'd pick a .45-90 at minimum, but the .45-100 will be a better choice. The .45-110 is great, but you'll have a hard time getting brass. I bought plenty back when the Normal .45-2.88" brass was easy to get.
Unless you plan on shooting off hand, heavier barrels are better. I prefer them to be longer than 30" personally, as they just seem more stable on cross sticks, unless they are a bull barrel rifle which is very steady on the sticks.
I think the ideal choice is my most recent Shiloh. 16lb bull barrel .45-100, 1:16 twist, 30" barrel, modern Rough Rider stock. It's set up for a 23" MVA scope as well as a LR Buffalo Soule and Windgage front sight.
Chris.