Don,

If the motor is a little heavier than the ZDZ I dont see you needing to add lead in the tail.
My CG is slightly tail heavy with the ZDZ 80 and no lead.

These larger planes are much more CG tolerant than the smaller ones..

As for replacement parts, My guess is dont expect anything quickly. Since Horizon isnt carrying this plane anymore replacement parts arent very high on the priority list.

Also,
I have videos of my Cap at,
www.rcsites.net/wgeffon