RE: Reference on setups and sail sizes?
Good show, mate!
I think that you will find that with the wider GO 150 you will soon be able to uphaul quite easily in a 1 m swell.
Until you get a larger rig, you will pretty much need to forget about using the fin to head upwind. When you don't have enough power to fully plane, you will need to tip your board slightly upwind rail down and use the shape in the bottom of the GO to take you upwind.
Yes, it's slow, but with only a 5.2 m2 rig and 12 knots there really aren't any other choices.
Hope this helps,