Anyone have any tips or tricks for doing the conversion?
Dang, I hate to watch you go down this road........................... again.
Just think of it as a Rubi 44 with more ground clearance 
....Which is what it is  ;D
Well, not exactly.  The weakness that I found in the D30 was the flex that allows the TINY ring and pinion to change relationship and break teeth.  The 44 ring and pinion is MUCH larger and stronger.  I also have the Alloy's and Super Joints, but I've never broken a shaft or joint.  I'm sure that's next now that I said it.   ;D
Fish, I've seen you drive that thing, and you're not scared of the skinny.  IMHO, D30's won't last unless you crawl'um.  Ask me how I know!