If you google "fremo freemo module legs" some ideas pop up. I settled on this for my LCCA modules
based on the below image I found on the internet. I eventually eliminated the second wingnut and just put a lag bolt in that wasn't tightened all the way down. The principal of this is to have the two pieces to the side of the leg be about 1/8" shorter than the thickness of the leg so it clamps it in place. In use, you only have to loosen the one side a bit to remove/insert the leg.
Brendan