T12s are higher then a T10 so the shelf would be closer to the rhp with a T10. Yes setting temp so the shelf is 90 would work but then the ground would be 80 and unless you put the hot hide on the shelf the ground under the rhp would not be the correct temp. Also bps are not generally climbers so a hot spot and hide on the ground would be best.
Sent from my SAMSUNG-SM-G890A using Tapatalk