Some people have had luck with Gonatodes species, but most are diurnal, so conflicts may arise. Chances are that any house geckos that you get will be wc, which would be risky at best. Most Hemidactylus species would do better with lower humidity and would prefer larger prey items. Other than the obvious worries about disease/parasite transmission, you may run into problems with uneaten crickets causing the auratus stress. If you are dead set on having geckos and darts in the same tank, you might want to research Lepidodactylus lugubris. I have heard that keepers in Europe have successfully kept these with darts. I too have wanted to do a large tank with darts and geckos, but in the end I decided that what was best for the animals was the right thing to do. So I just set up a gecko tank in the same room as my darts....not quite the same thing, but it works for me. Good luck with whatever you decide to do!