The safest substrate is something solid like tiles or paper towels.
Feeding is usually crickets and/or mealworms. The last time I had leos I grew my own meal worms in a separate Kritter Keeper. We used plain dry oatmeal as a substrate for them and fed the fresh produce like lettuce, apples, etc. Then we started the colony with a box of a thousand mealworms (regular size, not the supers).
Heat is vital for these guys. I used a heat pad under the tank and a ceramic heat emitter, both on the same end so there is a temp gradient for them to go where they need to be. I had a hide in both the warm and cool end. The other important thing is a shed/lay box. I used a small tupperware container and cut a hole in the side or top just large enough for them to get in and out. If eggs will not be an issue than moist paper towels are ideal to help hold the humidity up.
Use a feeding bowl to put the mealworms in. Keep the bottom of it covered in calcium/vit D3 powder (I like the ultrafine) this way the geckos get the Ca/VitD they need.
