I am on my third Monoprice Maker Select and the bed leveling is difficult. The z stop is always cocked and you have to back off the screws so far they almost fall off. So, I used the insulated washer and added the 0.1 washer to the base and after leveling the x axis with 2 CD cases, I leveled the bed in 2 minutes and was printing in 10. This was the fastest setup I have ever done.
NOTE: YOU NEED TO ALSO PRINT THE HEAT BED SPRING WASHER. PLACE EITHER 0.05 or 0.1 (I USED O.1) UNDER SPRING WASHER. Do two at a time, you dont have to do 4 at once.
IT WAS RIDICULOUS HOW QUICK IT WAS TO LEVEL AFTER DAYS OF STRUGGLING WITH COUNTER SCREWS ETC.
EDIT : - Created my own cupped washer in MP washer file