The other alternative, which I have used on my gaming board, is to just glue and screw some lengths of wood to the bottom of the MDF.
Just lay the board on the floor, flip the table over and mark the outline of the table on the MDF.
Then you can fix some lengths of wood to the bottom and the board does not move.
I did this and left a small gap so that I can put a cloth on my kitchen table first to protect it and put the board down on this.
It also makes for a tighter fit.