I use the Tri-Lynx blocks
for years and have been very happy with them. I had the small levels with the numbers on them. You pull in, check the numbers on the front level and use that many blocks under the low side. Easy. I have never camped where there was super soft sand. I would suspect that if you knew you were going to be camping in something like that a few pieces of thin plywood under the blocks might help.
FWIW I still have my Tri-Lynx blocks to use on my Class B+ moho even though it has power levelers on it.