Chevalier - The "pricey" system I have on my site should be totally unnecessary. Making the fixtures per the free plan I provide is a beginning wood-working project. The fixtures are for builders. It's a catch-22 in a bad way for me if you think about it.

Anyway, I really do think magnet systems are the way to go for most purposes. The only qualms I would have with your welding fixtures would be if the edges are not deburred or if they are so hard they easily leave dents in the piece you're building.

The reason I use thicker plywood isn't for strength but to avoid a narrow edge jammed up against my woodwork which will leave a dent that must then be removed.

Obviously if you're careful when you move these up against your work it shouldn't be a problem. But if you put a few in place and then pull the tail together it will make the fuselage bulge in places where there may be fixtures. Again, possible dents.

I'm just making general comments here as I've never actually held one of the fixture you are using so I may be imagining non-existent problems.

In any case, your system will really help you build straight airframes.

- Paul