Oh, I won't forget where DC will be run, already pondering that. Power I have more or less figured out, before concrete for the slab was placed I put PVC conduit below the floor where I would put TS, jointer & planer.
Watching Jimmy's video again, had I gone with scissor trusses having an interior 4/12 pitch, that would give me an 8' span where the bottom chord was at least 70" from the mezzanine floor. I wouldn't have an attic though and it's a bit too late to redo anything now.