Rather than add to the gigantic thread about this topic, I felt this deserved its own. In the thread I had complained about feeling eye stress from miscollimation but upon inspecting the divergence of a laser beam shot through the binoviewer, I found it to be less than 2 arcmin which didn't explain what I felt. @daslolo then suggested that the misalignment might be vertical rather than simple divergence and I set out to see if this was true.
First, I used the previous method of screwing in an eyepiece projection tube into the BV coupling ring and inserted a Howie Glatter alignment laser into it.
The BV was placed on a kitchen counter (these tend to be very level) and I checked the level with both an iPhone and a bubble level. The BV is shown above with eyepieces inserted but first I tested with them out and here is what saw about 4-5 yards:
Vertical misalignment! Inserting 35mm Ultrascopic eyepieces showed it was even worse with the expanded diffraction rings almost on top of each other. So could it be fixed? The Maxbright II does not have accessible alignment screws for the prisms but it does have adjustments for the eyepiece holders. To access them, first I had to loosen these set-screws completely:
There are three of them to hold the upper assembly to the bottom ring so I backed them out till they were sticking out but did not remove them completely as they're so tiny. It takes a tiny 1.3mm metric hex key to loosen them. After taking the upper assembly (diopter adjustment + eyepiece holder) off, you can see the bottom cell:
When the three screws are loosened with a 2mm metric hex key, the bottom cell/ring can slide laterally. I loosened them just a tad equally, put the upper assembly in along with eyepieces and moved it by hand till the diffraction patterns formed by the split laser beam were level:
Finally everything was tightened back. I won't have a chance to use the BV in a scope till probably tomorrow but looking into the eyepieces the field stops seem better aligned. Also notice the slight coma in the laser diffraction, seen also with shorter 12.5mm f.l. Ultrascopics. In a perfectly aligned BV this would not be present but with my earlier examination of star tests with the BV I don't think this is going to be a problem.