Flexwatt vs heating pad HELP!

So I got a new used rack that fits 4 41qt tubs horizontally. They are wired with 3in flexwatt with all separate plugs. The thermostat I have is a cheap petco one for now that does an ok job.I plan on getting a new one early next month. My question is is 3 inches enough to warm an adult bp? I have some older heating pads or strips (not petco or zoomed kind) that could fit under the sliding tubs that have a bigger heating surface for them. Should I continue to use the 3in? or switch to single heat strips (almost looks like flexwatt tape)? I would like to maybe change out the flexwatt that's installed now to cover 1/3 ish of the tubs but that wont be for a few more months. Please guide me bp netters! Thanks

Other info:
-Bf always complains it's too hot so he often opens the window so I can't keep a steady 70 degree room.
-Temp gauges read 78f-ish on warm side, and usually 89f on the warm

*9 warm side is ok 78 is on the low end of ok I personally would be concerned that the cool end temps (ambient air temp too??) would drop to far if the room temp cools much. Most racks are set up in controlled rooms 80ºF and 60% RH it is often considered part of the racks heating system.

I run a rack in lower room temps than you have, if it helps I can describe how I manage it.

The racks hot side is heated with 3 inch flexwatt This is controlled by 2 T-stat probes I found to keep the top correct the bottom was far to cool so I run a probe for the hot side top 2 and one for the bottom 3. The cool end temps are controlled by a strip of the low power 17 inch flexwatt controlled by a single probe of a third t-stat. It runs 79-81 bottom to top. The rack has 2 inch foam insulation on the top and sides the back is 1/4 with ventilation slots added. The rack is sitting on four inch foam to keep it from the cool room. The air flow runs back to front lower upper to lower, this allows the cool room air to be heated by the flexwatt. (each probe is also independently protected by a failsafe T-stat)

It was very complex to set up and perhaps un-necessary (just insulation might work) but I have accurate and precise control over hot cool and air temps that are inside each tub. The room temps from 64-80ºF do not change the tub temps more than a couple of degrees. Under 64 the cool end and ambient drop and over 80 there is no way to cool temps, so cool and ambient rise.

Thanks for the response. Now I sort of have a 'guide' for setting my thermostat up. I've also been trying to keep the room warmer. They seem pretty content. Only thing now is that their water feels really warm..do you think they mind? The bowls are in the middle of the tubs, so not very close to the heat.

no they don't drink standing water super often and cool water and cool air would likely do the same thing cool the core. Try insulating the rack and see if you can find a balance between human and snake.