One feeder e.g. cricket/roach of appropriate size once every three to five days.
Increase the feeding interval (e.g. from a three day interval to a week) when they scorpion is ignoring or rejecting the feeder, it simply means they are full.
When they are fatten up nicely, stays pretty much hidden and accompanied with sluggish actions. A molt could be coming up soon. Their molting intervals can range from every 2-4 months depending on their instar and your feeding regime and enclosure conditions.
A 3.instar Liocheles waigiensis is fairly small in size, about 1.5cm +/-
Hence, if possible, feed them juvenile cricket/roach would be ideal but they are other methods you may use:
[HOW TO] Guide to Feeding Young Scorpions