I see you worked it out, but as far as I know any G5 card OEM/BTO card (that will fit-not all will) needs to be taped to work in a G4. Some retail G5 cards-like the 9600 Pro(which is actually marketed as both a G4 and G5 card)-are a different story.
The same is also true of flashed cards. I may be wrong on this, but I think you can get away without taping in a Sawtooth provided that the card will work in a 2x slot(not all will).
In any case, glad you got it working-that's a really nice card for a G4. I haven't had a chance to do anything with my most recently acquired MDD(also a dual 1.42) but the 9650 is one of the options I'm considering.