I think really the only problem you have is too big of an enclosure.
I would suggest a small simple tub set up with a heat pad for belly heat controlled by a thermostat, and your temps and humidity should be almost perfect with maybe a little tweaking.
I don't think what the OP is doing is stupid, they were just misinformed. =\
I would try a hopper or small adult mouse your next feeding day. Try once a week to feed, if you can't find weanling or baby rats.