get a precarved stock from Pecatonica,
get a barrel from Ryan at MuzzleloaderBuildersSupply,
have him cut the dovetails for sights and underlugs,,if you not comfortable doing it.
if its a Leman, it seems TOTW has the nearest to being right trigger guard,
all of this would go a long ways in helping a 1st build get off to a good start,
Leman style is not a tough build, be a great starting point