I had a Shur-grip on my Kanati, but I took it off. The matte finish on my Kanati works just as well without it. They are a bear to put on, but do help on slick risers. I put one on the Caddo I had because the gloss finish was pretty slick when I had gloves on. I also replaced the worn out leather grip on my Mahaska with a Shurgrip.
Bicycle innertube would probably work if you found the right size. Overheating or sweaty hands is rarely a problem here during hunting season. I never really noticed a problem with the shurgrip during the summer though for that matter.
Leather wrap works, but sure doesn't stay looking nice as long. I haven't tried the tennis racket wrap, but don't see why it wouldn't work well.