If its flaking, it will be the thicker, rubberised type stone chip. This is what i favour. It dries rubbery, to deflect stones, which aids the life of it.
Ive only used it in litre cans, sprayed on with a schultz gun.
Waxoil is a thinner material. In my opinion, this would only be used for cavity protection. So inside chassis legs and the like. If theres a hole, get the lance in there and spray it!
It can also be used inside of doors, and rear arches etc (behind the trim panels). Im not a huge fan, i dont like the finish it leaves,and by its nature, remains somewhat tacky.
For cavity protection, i use Dynax S50 by Bilt Hamber. Comes in big aerosol cans with lance etc. One can should do a Teg, if your doing just cavities and inside doors and rear arches.
This is all based on personal experience and opinion. Heres a couple of pics of stuff ive done...
205 Gti, white stone chip, dynax s50 in any cavities. Im a sick little puppy and removed fuel lines, brake lines, fuel tank etc.
Honda EF8 , black stone chip, dynax s50 in any cavities. This was a mask and spray job.
Dynax in rear arches...