Right, so if they're standard that means they're either a 0 or +6 offset. And the 10" SBP drums means you have at least a 1/2" extra space because the track width is more than a 1/2" narrower for the SBP drums compared to the BBP disks.
If the OP had and extra 1/2" of backspace to make up for the change in track width he'd be set.
