In case some of you haven't seen this. It's super simple and super effective. Packing tape under the hold-down bar keeps things other than the tops and backs from sticking together. I've joined 30 something tops and backs, easily, quickly, perfectly, and I might have changed the tape once.
Nowt wrong! with that design jig Vic ..I like looking at designs for jigs and stuff. Here is one of my favourites it's the famous Gibson plate gluing wheel and lots of other stuff http://www.lashingguitars.com/art-225-parsons.html