Ok here's the mount, as i said earlier its the bike handle bar mount $40 mine is clamped to the plastic fitting on the boom. Ive used a few extra fitting to get the correct angle.
Heres the angle from the side, i have the lcd back pack and found if you can just see the extension clamps on the boom your not to far off but its very hard to see when its on it side at the beach.
Whether you do or dont have the lcd pack set it up at home you dont need to rig the sail take a pic look for the clamps
this angle is down to personal preference.
you can have it dead straight bang in the middle which is great for sailing in both direction but the horizon will be at the same angle as the boom
for wave ride i reackon this angle is spot on, you can always flick it the other way to film some jumps.
i use some of the spare rope holes to cable tie the clamp to stop any movement also cable tie the bolt fitting that holds the casing on just to be safe. Use a screw driver to tighten everything up and do it up really tight
Hope this helps
Gazza