So let me see if I have this right . .
You want to revert to your second back-up, and remove the Vista drivers from your system and use only the RC1 drivers?
If so, this should be easy enough . .
Goto your Device Manager and navigate to your printer . .
Right Click on your printer and select Uninstall
When the window pops up to confirm, check the box that says Remove driver software from my computer.
Restart your computer, and Windows 7 should install it's own drivers
Hope this helps
P.s. Have you tried the Rollback Driver option ?