I'm almost completely out of 72 myself but still not 100%. I just tried out the FrSky 8ch 2.4s with my set up thinking this would be it but they didn't work well on most of my planes. Work well on one but the planes that require more channels they didn't work on? Long story but I tried everything. I will have to get a few more Hitec receivers when I find the cash.
I just saw all the 72 crystals you had and thought you still kept them on hand for odd ball items.Other then a receiver every once in a while I haven't really bought anything new other then glue.