Your cmalping might be squeezing too much glue out, it's called "starving the glue joint". The tensor bandage is plenty enough.
Or there is some oil in the rawhide preventing the glue from binding to it. Try washing it with warm water with a little Dawn dishsoap. Then soak the rawhide in several changes of fresh water. I doubt the dishsoap would prevent the glue from binding, but I could be wrong.
Those are my two best guesses.
Gelatin consistency should be about the same as warm maple syrup. Thicker isn't so bad, but thinner means less glue and more water. I have always had better luck with using TiteBond II/III. For some reason it works better for me, but others have great luck with gelatin.
Good luck