I would be inclined to agree..all mine are at the cool end of the vivs...gives you the ambient temp rather than the basking temp...id put them on the cool end at the temp u dont want it to go above myself.
what i meant was if under the basking light at full whack the bask is correct then u wont want it to dimm unless the cool end is overheating.
so you would set the probes on the cool end.