you don`t want alot of humidity,these are desert locusts?you need warm temps of 32 -35 to get them to lay fertile eggs.for egg laying medium you can use vermiculite or sand,i have tried both and get better results with sand.The sand to get is propagating pumice sand from mitre 10 etc.Moisten it till its damp but not ringing wet and put it in small plastic see through coffee cups etc,you can use the polystyrene ones but I find the clear ones better as you can often see the eggs down the sides of the cup if you rotate it.positioning of the cups is also important,they should be flush with the bottom of the cage,you can have little holes cutout and fit the cups into these but must have room underneath,I have mine in a shallow cardboard box to acheive this,it covers half the floor area so its easy for them to get up on it and thereby think its ground level,a cup sitting on its own is too hard for them to climb up onto and you will get eggs laid willy nilly all over the place where they will dry out and be no good.change your egg cups as often as you find eggs but you can end up with heaps of them so I do 6 once a week,cover them with gladwrap and a rubber band,when they hatch you can put the container straight into the rearing cage or if you do it like me you get more babies if you recover it after each hatching(they dry out too fast once uncovered)