#1 I much favor the Triumph it is the best muzzle loader I have ever owned, an Omega is also very good.
#2 Any good high quality scope will work fine, some of the Knights hang fire with the new powderand it is the only powder that is noncorrosive and you dont have to wipe between shots with.
#3 Some people want max accuracy some want mag loads. The best answer is to start at 90 gr and work up every 10 grwith several different bullets most will start loseing accuracy by the time you rech 130 gr.
#4In a word no black powder guns shoot at the pressure levels as a shotgun not the 60,000 psi that a high powered rifle shoots, most places the avarage kill is under 50 yds anyway so the handicap is more only having one shot than any thing else.
#5 If you can use smokeless powderin all the places where you hunt you might consider a Savage, most of us can not.
#6 If you dont use the new Black horn powder be sure to clean the gun well the same day after you shoot it some powderis VERY corrosive, my inlines may never have any corrosive powder in them again I dont like the mess of scrubbing the with hot water or wipeing between shots; with Black Horn 209 its load shoot and if you feel like cleaning it is a matter of running a couple patches with Hoppes #9 through and an oil patch.
The Knights are a fairly high quality gun but I would not get one if I wanted to use the new powder; but if you want a heavy gun and you live where it is necessary to use thoses big heavy bullets with out a sabot some people prefer them for that, personally I dont shoot mine any more since I got the Triumph and a case of this newpowder.