CG,
If it's Henry rifling, odds are it's either 7-sided or 9-sided (odd no.), meaning your barrel slug measurement will be off - the #2 Musket usually is a .457 groove diameter. Would you mind posting a pic of your chamber cast, just to make sure?
Loading #2 is rather easy, and it is a quite accurate round - but you need to know what load your rifle was regulated for...
My recipes are as follows:
Either Swiss 1 1/2Fg or Fg, uncompressed or with minimal compression(around 80-84grs), veggie wad, and on top a rather heavy bullet seated to touch the rifling - Lyman Postell (457132) shoots quite well in my Martini's, lubed with a good BP lube. Gets about 1250fps in a 34" barrel. The 457125 would also work quite well. Size the bullet as required by your chambers, but somewhere around .458 would be fine - maybe even bigger if the fired brass will accept it.
I use fireformed cases, but if you want to use your rifle for hunting, you had better (neck-)size your cases. CH4D has an affordable die set, and they also have bushing neck sizer dies. Personally, I shoot fireformed brass, no sizing.
Check if your barrel doesn't have any load info on it - either visible, or under the forend.

For PP, suggest you 1st get familiar with the GG's - they are easier to get to shoot well, and don't require specialized equipment. below a diagram of the original Kynoch PP load for this round:

Basically, you'll need a .450-.451 grooveless slug, correct thickness of paper, lube wads etc. to make it work - it can be done, it is a lot of fun - but not how you want to start out with. Better to get some experience with the GG stuff, before taking the plunge with paper patching - it is quite a bit more delicate. FWIW, I also have a #2 Musket hunting rifle (single shot, Martini) which shoots just fine with the GG bullets mentioned - and yes, it also has Henry rifling. IMO Westley Richards did things just right when developing this round - it is a well-balanced cartridge, easy to load, very accurate and quite powerful - never mind the comments of CoTW. Call it a a Brit 45-90 (and then some...) I have now loaded up some 300gr bullets, which should give me around 1400 - 1500fps and a bit less recoil, we'll see how those work.
FWIW, my main use for the round is indeed LR BPCR shooting in a martini, and I do find it to be a quite accurate round, easy to load for - you just have to get the BP mentality..