I originally bought 25mm tubing. I will be able to use it on other rods but would not fit over the flair on the ends of the rods. I reordered 35mm which worked ok but I could have gotten by with 30mm. There wasn’t much shrink in the length but it really didn’t have to be that precise. I ended up cutting some a little too long but if you start at one end you can trim it with a little pair of scissors. They ended up pretty snug on the ends but I have only used them twice. How long they hold up remains to be seen. It looks like the same material they use on cheap little league baseball bats so I think it will hold up to summer heat. In regards to your original question the shrink on the length was minimal. The flair at the end was not an issue. It shrunk to fit either on the level prob the flair.
Good luck.
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