I've bent by hand and done a jig like Olson's, but the easier was a male/female set of cauls for the Fox...painless and quick...once the forms were done. If you standardize on a particular shape, it's worth the time to make up the forms. I use this one for my SJs...on the fourth use, so at least for folks using figured mahogany, curly anigre, or other fun-to-bend woods, a good investment. Both the bending caul and form made exactly as shown in the tutorial.

Sounds like you need to remake either the caul or the form...just allow for side thickness plus the thickness of foil, paper, slats, blanket, etc.

here is mine .. never fails .... the springs load the teniosn into the slat, and away you go. I let it heat on full (2.5 watt blanket) for about 2 minutes, then do the bend in about 30-45 seconds total ... its way easy to make, no mating forms !!! only the inside of the curve is required, I have mine overbend a touch..