We have been using paper tubes since we started. There has never been a complaint about them changing sizes.

I did try phenolic tubes on one set of prototypes, they were OK but the paper tubes have one big advantage. If the fit is a little too tight the tubes can be sanded to fit. You can't do that on a phenolic tube.

If you buy a plane, then go and buy a CF wing tube or other aftermarket product that is not exactly the same size, you are pretty well out of luck. But with the paper tubes you can sand the tube to fit.

TF