just resized some pictures of a job I did using the palace thick bed leveller ,there was a ridge in the floor and a few dips ,I usually use a 2m straight edge when levelling or if the floor is very badly out of level use tile slips as height guages and level up to these ,Using the straight edge method i find the high point of the floor and screw 2 screws either end of my straight edge,
I always mix with a whisk and then pour out the slc and screed back with the straight edge,I always get messy when levelling as I always end up getting back into the area I have just done to pull the straight edge at right angles to pull out any unevenness in the floor ,I suppose a pair of spiked shoes would be heplful and keep my clothes cleaner but never mind ,using the straight edge method takes out any guess work and also stops you from over pouring an area and adding to bumps in the floor. using slc is not easy and takes practice but the water based fibre reinforced levellers are really good and are far better than the levelling compunds of old .