The car wax adds more of a cushion/lubricity to prevent marring from claying. Claying in general cam marr the paint. Meaning if you marr the coating then you have to polish and re-coat. That is why Optimum recommends OCW with the wash , clay, wax method.
I would not recommend the claying towel. Bought one and hate it. It does not glide and left sticky residue on my glass when I broke it in and on the paint afterward on. I tried OCW and ONR and it would not glide. I have gone back to another manufacture clay alternative which is much better.
Hyper Seal can be purchased through the opti-coat website.