[Dukedesmo]

As above, on 2v engine's it's fairly easy. Good idea to take pics of the pulley positions as they may not be exactly on the lines but, one tooth out is a lot so shouldn't be tricky to get it right.

Once set, turn the motor over by hand several revolutions to steady everything and check there's no contact (and then check tension again) - I would strongly advise using an engine turning tool rather than the rear wheel/in gear as this doesn't give you any 'feel'.

With regards to tension, the allen key method is pretty good but is subjective and you maybe apprehensive if you're a belt 'virgin'! if in doubt err on the slightly loose side as they will tighten up when running hot and whilst they're unlikely to break through being tight, you may get accelerated bearing wear? - check the tensioner bearings for wear whilst you're in there.

This year, for the first time time I tried the frequency method using the Gates phone app and was pleasantly surprised at how easy and repeatable it was - I set the belts by conventional methods and then used the app to double-check and it was pretty much spot on, this on both the Monster and 916 so I'd definitely recommend it, along with your favoured method.

Good luck.