Are you gettin heat tape or heat Cable? I have a few AP racks ones with cable, and ones with tape. The racks with the wires have a groove that the wire tucks into. The racks with the belly heat tape also have a groves..the outside edges of the heat tape tuck into routed grooves to help it stay put. In both cases the wire and the tape are inside of the rack not outside. Almost direct contact with the tubs with maybe a 1/16-1/8" gap between the tub and tape/wire.

Does your rack have no routed groves? Was it made for cable and they are sending tape? I am kind of confused with what the deal is, do you have pics?