I've seen all manner of contraptions, and expensive protractors, on other builders sites for getting the 6 degree angle on the front spar HS710 and HS 714. The plans suggest a simple cardboard template, so how accurate does it have to be?!! Within 1/2 degree max I'd guess. Anyway, I drummed up my school trigonometry and as can be seen in pic 1 and 15Tan6=1.5 and there you have it - can't see even the most expensive protractor being any more accurate than Pythagorous!! Very easy to bend the tapered ends in the vice and compare.
I used the HS710 as the template and mounted both in the vice together, reason being they will both be at the same angle but more importantly I figured that if they're all the same angle that would prevent any twist being induced into the front spar.
