oh yeah... I forgot what a pain in the arse it was to insert the CyberVision3d/ScanDoubler combo card.
Here's what I did-
Took the Zorro 3 riser out of the Amiga, so I could hold on to it more carefully without putting stress on parts that shouldn't have any...
Take the ScanDoubler off from the CV64-3d and gently and carefully insert and remove each of the cards (scandoubler and CV seperate) one by one several times. This should "loosen" the slots slightly.
Assemble the CV64-3d / scandoubler, and reinstall the Z3 riser in the Amiga.
Insert a non-conductive shim of some form (I think I used cardboard wrapped in an anti-static bag) into the gap between the CV64-3d and the scandoubler module, so they won't bend around as much. This also gives you a spot to put leverage on the ScanDoubler, without tilting the CV3d.
Gently rock the whole assembly into place inside the Amiga.
Whole assembly took me a couple hours, if I remember correctly. I think I've only removed it once, since. ;-)