Stuck between not planing and planing

[JSW225]

Hi!

I'm trying to get planing and in the footstraps, but am encountering some problems. I have the Go 175, with stock racing fin (56cm deboichet?).

I am 6'4 and 300 pounds, using a seat harness. My sails are a 9.5 Ezzy Infinity, a 6.5 infinity, an 8.5 Matrix, and a 7.5 Simmer 3xc. I have the mast foot set maybe 1 cm in front of dead center (or at least the circle marks). I have the footstraps in the second most forward position, so they aren't outboards yet.

The problem is as I try to get planing, the board gets squirrely just as I decide to go for the straps. Sometimes it happens as I lift my front foot, sometimes before. Much like an indoor pet making a break for freedom upon seeing the outdoors, or perhaps more aptly almost like a Laser's deathroll confined to the front of the board, I lose all control of the board. I usually hook in before getting planing, so after the board's nose kicks left and right 6-7 inches four or five times in 3 seconds, I usually fall forward, though sometimes I get some spectacular catapults.


Any thoughts on what could be causing the problem? I was possibly looking to get a larger formula fin, roughly 85cm long. Would this help?