Thanks, Scott. Figured I'd ask as I'm in the same situation as the OP. Looking at undermounting a Zippyy long-shaft in 1/2" MDF without additional routering. Just in setting up my templates, I noticed the size differences in the Slagcoin template. BYOAC Wiki didn't specify one way or the other. As I certainly don't want to risk not being able to hit corners, I'll go 1-1/8" and be certain to center it really well. I figured, like Slippy said, the dust washer would cover it.