Some workbench design Q's......

I haven’t build a bench yet so take what I write here with a large grain of salt, but I would be concerned about the holding power of either plywood or SPF 2X4s for holding a vise or drilling dog holes. I think a hardwood would be better suited (same goes for mdf for the surface, I suspect SPF lumber would be better suited than mdf as mdf has no compressive strength so when you drill your dog holes they will deform or chip as you use them).

The overhang depends on what you do with your bench, some use the dog holes in the sides of the legs to act as places for holdfasts, extending the flexibilty of your bench to be able to use the sides as well as the top to hold things.

I suspect the possibility of what to finish you bench with is endless, I think I would choose not to finish the top at all. I periodically sand down the top of my work surface to have a fresh surface to work on (I draw dimensions and do calculations of fractions and stuff on my table so it gets pretty marked up :-). C. Scwarz has a pretty good book on benches from what I have read here (although I have yet to get this book myself :-(

I can understand that if you are using the bench for a outfeed table you want it slippery. Will that height be too low for a work surface? I know I like my work surface up a bit higher than my table saw…

-- ...it's rennovation time!!!