By saying slip harness are you asking about s floating yoke system like Hoyt uses or are you asking about a split yoke system like had been on most dual cams in th past? I haven't tried it and don't know if it could be done, but I have thought about it in the past. Just haven't taken the steps to really look and see if it can be done.
I'm trying to visualize what your problem is. If the cable is rubbing the cam then I would think there's a lot o side loading from the cable rod/slide or you have a weak limb fork. Just for info just how much clearance is there between the cable the fletching? It should be about 1/8" or a little more. Actually the less the better. Most of the bows I saw with the TRG, IMO, had too much clearance. When drawn the cables come in closer to center, but end up about where they should be at rest. This is just an opinion of mine though, and one reason I wasn't too hot about the TRG.
What you might want to try is a doglegged (bent) cable rod ajusted to get the cables closer to minimum fletching clearance and see if this helps. If you can post pics I would also like to see what's going on to see if I'm right. There's also the possibility that I'm wrong, but a pic would ease my mind about that, too.
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