MICHELIN AIRSTOP is what we have changed too after similar experiences on an RV-4 and RV-8 (so 5.00 x 5) wheels. It's a real PitA when there is a flat on these things - many screws to get the wheel pant off and if you try and drag it along with a flat it tends to damage the pant anyway.
We now bite the bullet and change the tube with every tyre change. This time (just done a tyre change) one of the tubes had been "welded" to the tyre at one spot. Carefull inspection makes me think that the tyre at some point had been locked (or scuffed - it is a taildragger
) and things got a bit hot..
You can feel the difference between the cheaper tubes and the Airstops. You do pay for it though, but we think it's worth the cost against the absolute b*ggeration of getting a flat.