Okay guys ... I get it now. ARF will mean you got no FRL to work from. Hence, you only want to get the relative incidence between the H stab, wing and the engine thrust line etc. I understand now that the engine thrust line is important as that will roughly be the centre of the plane. Thanks a lot guys!

John ... you said "In some cases, I have started with the thrust angle. I do this when I know exactly what the thrust angle is supposed to be. I set my incidence meter to read the correct (known) thrust angle on the thrust washer, then proceed to the wings and stab." Does that mean your firewall is set as zero and then you dial in the necessary engine thrust and that becomes the base for your referrence? So the referrence line is actually the engine thrust line? Am I correct to say that?

Matt ... so the laser beam is used to set your referrence line huh? Interesting ...

Really appreciate your input guys ... appreciate it a lot.