How to measure hot spots with temp gun

Hello all,
Do you measure the hot spot on the bedding, or on top of the hide? I have a hide under my gradient heat panel and keep the top of the hide at 90F. Should I take measurements on the substrate to make sure that is 90F?

If you have an rhp then top of hide is fine. Floor will be cooler

Sent from my SM-G965U using Tapatalk

Okay, I just wanted to make sure because she has been finicky eater the last two months. I want to make sure her temps are within the desired range. Thank you for your input!