Speaking for myself, the cost of the animal is not relevant, you agree to take on the responsibility to care to the best of your ability for it or don't get it in the first place. This is my moral compass not yours I see what you are saying but if the animal is 10$ or 10 000$ the conditions it is kept under stay the same, as close to ideal as you can manage.

that said the equipment you use to get to ideal is not relevant getting there is. This threads sprite is about what will make that easier and what will I need I have not though of. It is one of opinions from people whom understand what is available.

My professional job deals with sensitive equipment and part of that job it to calibrate them and make sure they work reliably. I do a lot of testing to find the right gear for my work place and to find and solve design flaws before they cause problems.

I started to do consulting doing exactly this. i have been hired (and agreed not to relay any details of whom what or why) to test hydrofarm thermostats for use as a single component. Tests are still continuing but the relevant tests are mostly done. I can explain some of my results.

The accuracy of the probe is very poor.
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This is a photo to show what I mean this is after 10 hours in stable room temps. the control thermometer (silver) is a traceable thermocouple type and is spec'd at 0.1ºC error it is re-checked yearly.

26.9ºC is 80.42ºF this is the correct temperature. the hydrofarms reading 81.6ºF, 82.4ºF and 83.8ºF is not very accurate these are the 'new and improved accuracy' version and came as samples from the supplier.

the next part is to check the probe response. The hydrofarms (all) were set to 85ºF and then the probe was cooled and heated to check when the units came on and off. Started heating at 84.3ºF avg. and shut off at 86.7ºF not stellar but acceptable.

The units were then connected to a heater and probe placed directly on the heat the ambient room temp was set and stabilized at 60ºF and the units set point to 90ºF An accurate thermometer was connected to a data logger and the test ran for 24 hours. The average high temp was recorded at 113ºF for the total period and all 3 units. The average low was recorded as 85.7ºF This is a spike induced by tough conditions and slow probe response.

the test repeated at 70ºF ambient temps and the range reduced 107ºF max and 88ºF. The test repeated again at 80ºF and the range reduced again to, 99ºF and 87.8º.

I have tested a johnson (not as carefully as I was just curious) in a similar way the on off points were closer and the max and min temps recorded on the heat element were closer but it still was not great. this is a 'torture test' to find how bad bad is.

The advise I have based on this and my experience with other on off units is this.

Avoid direct heat (heater directly attached to enclosure) and or place the heater on something that is slow to heat and slow to cool (simply something that is heavy, weighs a lot.)

Avoid using the unit with great differences between the set point and ambient temps.

It would likely work really well with a rack where the heater is fastened to a shelf and the tub sits with a small air space between them (the 'rails' found on most tubs) and or in a regulated room. Used with a tank or like in a semi regulated room.

The use with the heater stuck on the bottom of a plastic rubbermaid tub or sterilite in regular room conditions (65ºF to 73ºF) it is possible to come close to replicating the results I got in my test and see spikes inside the enclosure. It is quite likely to stress the snake (guessing) and that result in failure to eat and possibly other health issues.

Quite some time ago I started testing one of my herpstats, The probe accuracy was very very good so close to mine that the error it has makes the test not worth reporting basically as accurate as I am capable of testing. The heating test gave a max and min less than a degree apart and I stopped there as there is no point it continuing. This is why I recommend a proportional units, I own herpstats (4 pros and a 2 and hd) but the others (ve ecozone, habistat) use similar technology so I'd expect the practical heat to be so close to make no difference. The differences is fit and finish, set up menus and extra features.