It's been so long since I've ridden the 52cm, I can't say how it compares to the 54cm V3. However, I found the 54 fastest downwind just do to less drag (on the same tack as the 60). But a good racer can go off the wind less and get to the mark faster.
I think they are pretty similar in speed in chop, but they feel and sound different. The bigger the bottom the noisier it rides, which can then be perceived as speed.
Here are some GPS tracks. First, the 54 wave riding. Way more fun than I thought it would be.
Then, the 66 on the big upwind and downwind lines.
A moment to pimp here. As far as we know, we are the only shop in the US with them still in stock.