After using the beadlock system I have noticed a few minor problems that can be fixed easily. As well as the known problem of lining up the pencil line I noticed problems with deep mortices and also when using the spacers.
There is a small amount of angle allowable (slop) within the holes in the metal block. When using a hand drill I guess the tendancy may be to angle the drill slightly. I have tried using a drill press but never seem to be able to align the drill and block accurately enough.
Hint 1. Shorter lengths of beadlock are less likely to result in an angled (misaligned) joint.
Hint 2. Make solid metal spacers as the plastic ones supplied can be compressed slightly and give inconsistant results.

When I created a misaligned joint (noticed after gluing) I cut the joint with a saw and drilled out the beadlock to start again. Lost a few mm with the cut but at least I could fix easily. Cant't do that with a tenon!