Is it advisable to mount wheels on the underside of the cabinet? I'm not sure if the cab will move or not under play. I was thinking of installing non lockable wheels on all 4 corners. The lockable wheels tend to be too large and tall.
On the other hand you can do what I did for my cab

This works great especially if the cab is not huge and too heavy. You lean the cab (using some kind of handles) and you can carry it around easily.
This is what I am doing and it's quite practical (Ofcourse I don't have a big cab, but still is quite heavy)