i wouldnt do it either beccause if one RHP fails where th t stat probe is the other tank will get cooked and you will have 2 dead snakes. each tank should get its own probe.
Also i have two tanks stacked and the top tank gets a cooler temp even tho both hot spots have to be at 92. the bottom tank heats the floor where the RHP is. so my top tank is set to 84 and my bottom tank is 87