Looking good - thumbscrews are a good adjustment - you may need a locknut or jamnut on one side or the other to ensure nothing moves after alignment. Otherwise, I'm looking forward to your results. Being easily able to retweak an alignment is a big plus on these systems. Having a 3D printer certainly makes life easier - especially when having to re-iterate through a design - I can feel another project coming on
You're missing the z axis in your drawing - all your alignments are in yaw, not pitch. xnaron's document is correct (albeit a bit chingrish
) As shown in his pdf, when you have mirrors 1-2 and 2-3 fully aligned on centres, you have no adjustment left bar the laser pitch, yaw and z to ensure concentricity with the final lens and the tilt of the beam to the worktable.
An interesting point in the pdf was switching the lens from curve to top (where it should be surely?) to curve to bottom and repeating the cuts - then choose the best result - must try that at some point for interests sake if nothing else.