Tempgun or accurite

I am going to get a rack for christmas and I'm thinking of building one too but every plan for rack building is talking about putting your probe on the flexwat but I really don't want to buy a accurite for every tub. Is it ok to get a tempgun and would you want to read the temperature of the flexwatt or the inside of the tub? Also what should your helix be set at? I don't have mine yet but I want to know at what temp it should be set. My parents keep our house at like 72 most. In the winter and about 80 in the summer

I think you are misunderstanding what is being said. When they talk about placing the probe on the flexwatt they are talking about the probe for the thermostat.

When it comes to measuring the heat I have both an acurite and a temp gun. I just have one of each and move the accurite around from tub to tub mostly to check humidity levels.