Caging 2 snakes, but more in future?

I plan getting 2 female hatchlings/yearlings and am unsure how to cage them yet - I'd like to buy them a male about a year later, breed them, and maybe have some holdbacks and expand my collection and breeders. Since for a good year I'll just have 2 ladies, should I just keep them on a shelf with appropriate dimensions with their own separate UTH (ie zoomed etc) with thermostats? Is it worth rigging some flexwatt heat tape for just 2 snakes?

And, in future, how do you go about wiring your flexwatt out the side of book-shelf style racks? cut holes so the wires can exit? I'd get an open freedom breeder type rack but I think the implicative commitment kind of freaks my boyfriend out :D I'd rather stick to something shelf like that's a little less industrious looking in the spare room.

Thanks!

Buying the flexwatt will be cheaper and just as effective as a heat mat w/ a t-stat. As for housing, search around for the many options to see what appeals to you the most.