[Gustav]

Thanks MetalMan,so are you using that shaft as the output shaft with the diff driving it?(ignore this i've just noticed how stupid i am)
I was thinking the other way round,using the e-maxx shaft with the strobe and spur with an e-maxx input gear driving the diff gear.

Do you have pics of your set up somewhere on line i could check out because i think i've got the wrong end of the stick so to speak.(another edit, i've just realised you must just be using it as a centre spool,no diff at all,silly me.No need for pics sorry.)

I just saw your edit,now your talkin',I don't see why that couldn't work.I'd be fairly long though by the time you factor in the slipper spring.You could use a collar threaded on the shaft to tension the spring like on that ofna slipper.
Get that to work and we'll have to get your RC Monster status thingy upgraded to Genius.