I agree with the others... ANY heat source MUST be on a thermostat. There just really isn't a safe alternative to this. Yes, a good thermostat is expensive, but it's probably the single most important fixture for keeping your BP. There are several tricks you can do with a screen top to help a little with humidity. Getting a piece of plexi-glass to cover part of the top, or covering as much as possible with aluminum foil will help too. Add an extra water bowl, or a bowl with a handful of sphagnum moss in it that is watered down will help add some humidity. Spend some money on a good thermostat and some good thermometers/hygrometers and you won't be disappointed. I promise.

As for the feeding, you can feed anywhere from 5-7 days until they start to mature, then you can go a little longer in between if you want. I fed my bp every 5 days until she was about 200g, and then I went to every 6 days. She's now about 500g and I'm going to every 7 days, as her meals are getting a bit larger.