Dude;
Just a couple of "weird ideas", on your 7X mishaps:
How far down, in volume, is your tippet spool? The closer you get into the spool of tippet, the tighter and curlier it is, coming off the spool.
If you're not, doing it, try straightening out the 7X before or after tying it onto your leader. (DON'T use, one of those rubber to rubber, made from old inner tubes, type straighteners they can easily "burn" and weaken your mono or even Floro, material).
If nothing else, could it be the brand? I love "Frog's Hair", but that's me. I used to have an awful problem, with spirals and tangles, when using some weights of Climax!? I, don't, however,since switching to both Rio and Frog's Hair tippet.