The bars should only be lubed with Vaseline as per Reese instructions. This was covered in another thread in the past week. Maybe in the towing forum? A very thin layer of lithium grease *may* work, but I would read what was said about lube in that thread. Lube is usually only used if there is objectionable noise - friction is needed as part of the operation of the dual cam hitch.
If you have higher TW, what rating are your spring bars and what is the new actual TW? Maybe you need higher rated bars? You can flip the cam arms from left to right to get back to a new surface. Cam arms do wear excessively but I think it takes a lot of miles and/or high TW. I could be wrong, but I think the bar "notches" don't wear as fast. Also, don't forget to mark your bars left and right so they stay matched to the wear pattern on each side (maybe you knew this already).
I think it would help to post photos of the wear on each bar/cam surface and a side photo of the TV & TT hitched up to see how it looks.