Actually placement of a probe is important as that is going to determine the temps. I personally run a Herpstat 1 on my big BCI cage and a Herpstat 2 to run my baby sunglow and pied cages. As long as you don't exceed the wattage rating on the T-stat, you should be fine and generally you want 1 t-stat per cage. The exception is if both cages are exactly the same, then some people use 1 t-stat with 1 probe in 1 cage to run 2 cages but I advise not to do that. I use RHPs and CHEs for my cages and I put the probe about 2" to the side of the heater and about 1" from the floor. Then I dial in the Herpstats with my temp gun and my thermometers on the cool side until I get the right temps I want. For me personally, I run both my Herpstats set at 85F and that gives me a good gradient. Also you will know you got it right if you see your snake going from cool side to warm side and vice versa. Always on the cool side and that means you are probably too hot, always on the hot side, means you are probably too cool. And finally, I only use Herpstats. I have a Hydrofarm that I used to use on UTH but since I ditched UTHs, I just use the Hydrofarm as a backup. They work ok for UTH but the temp swing on it is too much for a RHP or CHE imo plus its an on/off type which sucks for RHPS and CHE. Use a dimming T-stat for those.