Doug, I too used to wear just a safety belt until I read one too many horror stories about the result of falling in one of those. And -- after switching to a harness -- I experienced the same difficulty. I usually solve the problem by either sliding the cloth rope which goes around the tree way up or way down. If it's up high enough, you can manuever around under the attaching rope. If it's down low enough, of course the opposite would hold true.

For safety's sake, it would probably be wiser to move the rope up -- since that would shorten your fall in the event it happened... but that limits your mobility even though you can now turn to your right.