He has recently been playing the MP-59's. He did use the 63's for a while. MP-64's probably feel a lot similar to his 63's.
Thought he used the 32s, then the 62s, tried the 63s and didn't care for them (in spite of the glowing reviews he gave them while on the driving range in a few Mizuno sponsored youtube videos) then either stayed at or went to number 1 in the world with the 62s back in the bag. He's pretty much played like garbage since retiring the 62s.