Well you've obviously put a lot of time / money / effort in to things . I'm still unclear on some points tbh
Photos will certainly help - consider downloading the free TapaTalk app which is fabulous for uploading photos ( one click ) ..
As regards the thermometers / hygrometers ... do they have wired probes or are they like these ?
One thing I noticed about mine is that some prefer the cooler temps and will spend time in the cooler parts of their vivs which sometimes is in the mid 70's even though the suggested temp gradient - range I commonly see is 80F on the cool side up to 92F warm side ...
I'm wonderingly you maybe better having the second heat mat maybe halfway across the viv then you'll have a warm side - warmish middle and a cool end ??
You've also got two lamps in there and I'm not sure where they're situated but presumably they will be giving off more heat as well ?