ROTS Windu, Drallig & Kenobi vs Dooku, Grevious & Ventress

If he mastered the best lightsaber form in two years, he is pimper than anyone else in Star Wars. But that is bogus information.

Release the chinchillas!!

I thought he trained with 3, then moved on to 2 as he got older.

We don't see Dooku use Form III. If anything, he probably knows some Ataru and some Shien, considering his movements in ROTS.