I'm gonna get a couple emperors in a couple days but I have a couple questions. I'm gonna use a mix of peat moss and coconut fiber how deep of substrate should I use. Also would a portion cup be ok for water.
Greetings 'greenmonkey51' and welcome to the hobby;
I would suggest to first set the tank up several days before you bring home your scorps so that the temperature and humidity will stabilize.
As far as a suitable enclosure I would highly recommend the false bottom set up. First put down a layer of aquarium gravel 2.5-5cm (or 1-2") deep (I use stones around 2cm or 3/4"). Second put a vertical tube into the gravel rising nearly up to the top (this is so you can add water to the gravel layer) (screen off the openings so your scorp or crix won't climb down the tube) Third pour in water to just barely come up level with the gravel depth. you should only need to add water every month or so. Fourth put in about 10-12cm (or 4-5") of substrate, the peat coco fiber mix is good. tamp/pack it down firmly the emperor will burrow. Fifth add you decorations, any items found in the yard should be baked at 400° for a couple of hours to kill any 'critters', any big or heavy items that could crush your scorp should be buried down to rest on the stones/gravel. Sixth put in a water dish deep enough for the scorp to 'bath' but not too deep so it can't get out. I don't know what a portion cup is but a shallow dish 2-3cm (or 1-1.5") deep would be good, if the walls are too steep or the dish too deep drop in some aquarium gravel to make ramps. Seventh put a lid on it, I put a screen top on first then put a glass sheet on it so I can adjust for air flow. Eighth you need some sort of heat source, an external heating element, IR bulb, UTH mat on the walls or something
I use around 4" deep coco fiber, and my emperors burrow down to the stones. 2" deep substrate will suffice. Make sure the peat has no additives or chemicals in it, also make sure to keep away from pine and (I believe) redwood type of substrates due to the oils in the wood and such.
I have my emp tank all setup with temps in the high 70's, I had to use a small red bulb to do it though. I still have some flexwatt on the side of the tank. Would it be ok to turn off the bulb at night and leave the heat mat on. A couple parts of the tank would dip in the low 70's but there would still be a good part that would stick to the mid 70's.