Having done all this, I'm not sure I'd do it this way again. It might well be faster to layout the positions with compass and straightedge directly onto the top. Either way, you'll want to use a scribe rather than a pencil. Scribe lines are hard to see, and impossible to photograph, but the scribe and compass points click into them, allowing a precision that pencils simply cannot match.
Chris I blame you for all these altars that are being built today and now you thinks we over thinks ’em–huh. You whipped the masses into a frenzy— now Woodworkers are trying to out pretty each other–out wood species each other –out Rube Goldberg each other. I made 2 benches in 30 years neither had a through dovetail but many were made on them and I have no idea but I would bet a dollar that neither weighed 280 pounds but they both had tons of wood on them. If you want the bench as a destination god bless but it was intended as a mean. Thats my rant I could be wrong
The reason I'd cut out the rectangles in the vise support was that I'd intended to put a benchdog hole through each, and I wanted the thickness of the top to be the same for all of the benchdog holes. Where I messed up was in not cutting out the ends, between the bolt tabs. I'd intended to put a benchdog hole through there, as well, but I'd forgotten to cut out the segments prior to glue0up.
Grizzly is a company currently undergoing an upheaval. This brand was once known as a manufacturer of professional grade tools and equipment for woodworking products. Though, in recent years, that reputation has begun to slip a bit since being bought by the Chinese company SIEG. These days, whether the Grizzly product stands up to its previous standards of excellence often has more to do with what you are buying than the company itself.