I tried aligning my new Beambox Pro using the instruction provided but found it very hard to measure the location of the beam relative to the mirror rings and the lens holder tube.
So I invented some acrylic targets that hold the tape and enable easy and accurate measurement of the alignment errors.
Please ask me and I will send you the BeamStudio program to cut the targets. I have removed about 1mm with engraving to form a ring that fits neatly into the holders. There is one for mirror 2, one for mirror 3 and one for the lens holder tube.
These fit neatly on the holder with the white tape and can be removed and viewed from the back to see exactly how close to the centre the beam is.
Finally, to check the beam at the bottom of the lens use a small piece of Blue-Tack instead of the white tape. It’s then really easy to see if the black spot is in the middle of the hole as the Blue-Tack holds the shape of the hole. Very hard seeing the outline on the white tape adhesive!