Seems to me that because the cutting forces are not balanced using the hole saw that way, it should be tight on the arbor somehow. I haven't had the experience of one over-tightening, but I can sure see it being a pain. I would want to have it snugged up securely on the threads, then pinned so it can't tighten more. Probably not a lot of meat to work with on any standard holesaw arbor to accomodate your own pin drilled to suit, though.
I would be making my own arbor for the holesaw, with a backing flange large enough to turn a recess into for the holesaw to light press fit into. Then drill and tap a central hole for a bolt, which will be able to hold the saw into the recess with a made-to-order washer. I would still use a pin to prevent the saw from spinning, and that will prevent the bolt from becoming over-tightened as well. The pin could be press fit into the flange, or it could be part of the homemade washer, and fitting through the saw and into a hole in the flange. You wouldn't need to use the threaded mounting hole in the saw at all.
At least this gives you a rigid setup, and some support to keep the saw concentric. For any size of holesaw that's longer than it's diameter, you can afford to have some of that length buried in a recess in the backing flange. For wider holesaws, where the length of it has to go partway through the tubing in order to complete a cut, you wouldn't be able to use the recess idea. But in that case, the flange could also be wider and would give some room for you to drill and tap for more than one socket head bolt. I would still use a homemade washer sized to suit to sandwich the holesaw to the flange, for best rigidity of the setup.