Hi Scota;
I have made three banana box releases using Ken's tutorial, two using the 10d, 3" masonry nail and one using a repurposed hack saw blade with a button soldered on the top of it. I liked the hack saw blade release more than the nail. The reason is using the blade is faster and it works fine. "Easier," but not easy, if you don't go about it with some thought and planning. PM me if you want to discuss how I went about making mine. Also, if you decide to go the masonry nail route I have a supply and would be happy to send you several.
dave