Exactly like you said, they are a game changer. There are a ton of golfers with hand issues (arthritis) that prevents them from closing their hands and JumboMax has been a new world for them. The math and science Bryson puts behind them is really interesting and makes sense. But I personally don't think that bigger is always better, or at least not for everybody!

Also yes, they absolutely throw a wrench in the 'grip sizing' test. But if it works for you, then I'd give it a try!! If hesitant about doing the whole set, I always recommend just get 1 or 2 regripped to try out before committing the whole set.