I'll be interested to see how you go, my Dad has an unmolested Osprey supertarget with the standard beech stock, I've not been let loose with the internals (yet) I love the side lever cocking and though the loading tap has its own problems I find dropping a pellet into the breech really easy with cold fingers.
Finally is the trigger, I've heard the Omega or maybe the Vulcan 2 stage blade will fit.