RE: Freeriding the GO 170 with formula sail
Whats your weight Ricjk ?
I(95 kg) still have a GO 180, model before the friendship,( 280 X 80)
And I still use it sometimes with 10,4 Nitro 3 and 66 cm DEB R13, works fine. Problem is, older 9-10,5 m2 formula sails are for highwind use. So for sailing on the light edge(8-10 kn) your weight, and wind quality and skill is important.
If you are >85 kg, a modern freerace, like Overdrive, GTX,V8 in a 10m2 size, or a 11m2 formula sail.
<85 kg, a 9,8-10,5 m2 formulasail does the job.
the older Nitros' are real flat sails, no grunt, but fast and stabel in poweret up konditions.
Maybe you can save money on older formula sails, but remember, you do NEED the right C 100 % mast, and 260-300 cm carbon boom.
Freerace sails, like the overdrive work fine with 75 % C masts, and shorter booms.
Dont know the KA.