I have over the years had 5 RB,
Couple of thing to know Before you touch the trigger, and hammer...Do Not mess with the angles between the hammer and trigger, do not grind on the mainspring, the block lever is also the trigger safety, if it does not touch when the hammer is cocked, if you pull the trigger with the hammer cocked, the hammer will be in the fire position, when the block is closed, the rifle will fire, (I know this from experience)
for the trigger spring the Rolling Block guy makes a spring for this, from wire
for a target trigger, A SSet trigger works, but is a PIA to install,if so incline I have the drawings and instructions to do so, with cast parts