Sorry, I missed this post. Still recovering from spending Christmas with Kristine's sister and brother and law, its nice to know that a couple can argue all day long, get some sleep and then start it up again the next day.
I have some experience with stacks, My Nexus stack has 5 kites with the one piece lower spreader and 2 with a 2- piece, I have never had a problem with the lowers coming off except after a crash. I do however experience the problem with my No-Na-Me stack. My quick solution is using a rubber band from one side of the lower to the other to add tension across the center T.Here
are some thoughts on link lines and pigtails
Remember to have fun