I use vision cages for my adult boas, I have 40 watt incandescent bulbs for overhead heat and supplemental belly heat for the colder parts of the year and constant belly heat for the floor cages.
As far as humidity is concerned overhead lights do tend to dry out the enclosure, I can control that to some degree by blocking off portions of the ventillation screen in my cages.
I think the best method to control humidity is a slight misting two or three times a week, this also alows you more contact with your animals.
Depending on the style of cage you will be investing in you eill probably find most of the better quality cages will hold humidity much better than your old set up.
What cages are you considering?
Joel