The VMO/MMO on the A330 is 330/.86
The A/THR works well on the thing, except for maybe in turbulence. It tends to lag behind a bit and the result is a lot of 'pumping' between idle and climb thrust. The procedure is to disconnect A/THR and set thrust by N1.
The catch is to remember that you're not in A/THR anymore and keep an eye on your speed....
