Thanks, problem with moving the mast fwd is that the foil becomes more loose I find (plus I am already at the max for my board), and this foil is already a step up for me.
Will try to shim stab a bit to avoid spending more money
Using 450 would be the other option, but defeats prob. the purpose of a high aspect, fast front wing
I find that I do not like the 450 with 633 and 683, while the tracking becomes much better and everything feels more stable, the front foot pressure is just too much, even with mast all the way back on my board - 483 feels better in that regard.
Not sure if surf stabs actually fit on the 647, haven't tried yet.