So I have been recording all my readings in my homemade enclosures for about 2 weeks now and I have a question or two. I have 2 weeks to go before the expo and purchase of 2 BP's. I am currently using about 1" - 1.5" thick layer of Reptile Prime in each cage over an area of approx 36" X 24". I am in the middle of winter in CT so there is no humidity in my house. I think we were at like 22% when I checked 2 weeks ago. I find myself adding 1 - 1.5 cups (yes I've been using a measuring cup) of water every day or 2 to the substrate and then mixing the wet stuff around to spread it out. This generally bring the humidity up to around 70% within a few hours then over the next day or 2 it falls to around 50%. I know that this is in the except able range. I do have a large water bowl directly under the RHP in each cage. Also ambient temps are holding steady at 86F +/- 2F reading from an accurite thermometer, with the hottest spot on the hot side being 91F and the coldest spot being 78F as checked with temp gun. At the moment I do not have any hides or clutter in the cages. Trying to get basic readings and settings down so I know how to react to changes.

So my questions are:
1. Any suggestions to do things differently? no adding a humidifier to the room is not an option.
2. Is it ok to have swings in humidity like that as long as it stays in that range or do I need to figure something else out to make it hold better?
3. Should I just Relax it's good as it is?