MDF expansion and contraction. Anyone know how much of a problem this is with MDF?

When I used to work at a cabinet shop we used to use bondo on MDF with no cracking or ill effects. To finish the finishers used a clear sander sealer then bondo then the final coats of lacquer etc. The black lacquer look used to be done with a few coats done within a few hours. The finish guys also used to do a faux wood grain using paints and lacquers. After the "fauxing" up of the MDF it was finished up with a clear coat lacquer.

To finish my Mlord docking station i plan on using a clear sanding sealer then some bondo. After that I plan on sanding all smooth to 320 grit then reseal using the sanding sealer. Let dry overnight and if needed buff lightly with 320 grit sandpaper. Then, using a spray can of black lacquer, place three or so colour coats over the sanding sealer. After this dries I will overcoat with one coat of compatable clear lacquer (the same brand name usually).