There's a lot to be said for a solid freestanding base which won't rack,
should materials for a top not crop up.
might as well post mine, which has proved to be super versatile, having a floating top.
Nice and all the joinery aspect of things, well not this bench...haha,
but it doesn't lend itself to altercations should one change tack down the road.
(a thicker top would be nice but would make the bench too high)
I suggest using knock down hardware, M10 in this case was good.
Some have brought up needing to cinch down these as they come loose....never had to do such a
thing with this bench.
Space for feet underneath, two pair of strechers for rigidity, and space for a large clamp to fit under,
will likely give one very very little choice to do much designing,
especially if wanting a thicker top.
Two "solid core" doors, like fire doors for example would provide plenty of thickness,
or whatever, might need to be shimmed/choked up to stop it sagging as these doors are heavy, would be an instant solution.
I'd not be dissuaded from using steel either.
Once again just an opinion as I was without enough timber to make a top at the time,
but had lots of shorter lengths.
Was planning on having a taller bench, but plonked this lab top on it one day,
and by chance turned out to be perfect planing height, which is the most important task for me,
not really wanting a PT for multiple reasons.
Someday, I'm likely going to lop an inch off the handles on a pair of large f-clamps,(middle isle inliddles) so they fit underneath.
ps Very nice bench John.
All the best
Tom