When my mat goes in the maker it just slides itself to make it work without any troubles. Now when i need the occasional tool, it rolls out without a fuss.
I put 4 wheels on it and as soon as i turned it over and the weight on wheels 2 wheels broke off. The weight on the wheels caused the wheels to break off.
Big wheels are nice, these roll and pivot well. They move very smoothly. Dual locking feature added bonus.