k, those temps sound better. The cage furniture, not much of a factor here as long as it's contributing to a better enclosure settup and not causing problems. Not breeding advice, just common sense I guess.
Every species is going to be more subtle to breed than others, and you did bring up some points to think about. Breeding generally occurs in what we think of as spring. That means the daylight is lasting longer, temps are getting hotter, and rain is becoming more common. Dumerals are from Madagascar correct? That means not they experience more of a rain/dry season than a winter and summer, and daylight hours should change slowly from 10 hours to 14 or 16. Not nearly as much as the 8hr to 20hour range seen up here in Edmonton 
Honestly, I"ve never bred dumerils, but friends have and they havn't found it too difficult, very similiar to boa constrictors. In otherwords, you probably won't have to do much of anything. Double check with the boa forum for more details. If you have any problems, it will likely be more related to getting the babies to eat, but that's a whole different story.
Ian