For my Viv of similar size I use a 100w basking lamp and it's excellent. That and my Dimmer Stat hold the temps spot on.
And for the Crix I use a big plastic (toybox) tub from Ikea. I've sanded the sides to about halfway up to increase the crawl space, and stand it on a heat pad. I have to clean it out every few weeks to keep the s
t and smell down, but it's no great shakes.