And if you're going to epoxy a joint and have to hold it while the epoxy sets, you're screwing the strength of that joint from what it could be.

If you want a strong joint in a very short time, use CA. It's also lighter buy a huge margin. And is going to be stronger than 5minute by a huge margin.

One of the other benefits of 30minute epoxy is that after you've glued the joint and stabilized the pieces (masking tape for example, is a wonderful building tool) you can wipe the excess epoxy that's squeezed out of the joint. That reduces the weight added by the epoxy to usually less than half it'd be if you left the worthless excess. Very, very seldom are fillets of epoxy worth the weight penalty.