Some photos of my takedown bench. It's quite sturdy for its weight and size, due to the splayed legs. i'd say more weight, the better, tho' that can a detriment as you get older. The ropes tighten the clamp effect of the legs on the plank top. In the sketch in the previous post above, the notches in the plank to receive the legs would be a great boon for stiffness.
Two legs, bound for life by rope. In betwixt the legs, there is the stretcher, then the stick for tightening the rope. Note the lower leg lost the little nub at the top, chipped off during assembly/disassembly.
Top end of the leg, which slips over the plank. This is yellow pine, and the nub at the top can split off. I would change the
design of the leg to be more like the sketch, which would be much sturdier.
End view shows the tightening sticks. If they are too long, you cannot twist them up tight, as the table top is in the way. If too short, they will not stop against the table bottom.
This is the same idea, but uses threaded rods to tighten the legs. Also note the leg tops don't extend beyond the table top.