sorry i can't help you out on this one...
just came here to say:
wo - f*cking - ow man !

i've always had a weak spot for the 24v sierras and similar.
please, keep us posted on this one (more pics, as soon as you have more).
it's a cracking project this one of yours ...

so far you did great !
hope you find all the help you need in here,
(for sure you will)...