Aah that's good to know, I thought the short dovetail was at a fixed location and could not be shifted along the length of the L-bracket. Thanks!
I should say that it is a standard L-bracket ('Feldsteckerhalterung') and it turned out that it is not well balanced and sufficiently stable. I will replace it with a stronger one.
So far I have a very good impression from the instrument, well machined mechanics. I could check the optics during daytime with Morpheus eyepieces wich 12,5,mm, 9 mm, 6,5 mm and 4.5 mm focal length and could not detect any misscollimation.
A small surprise, total mass 4.3 kg instead of 3.6 kg specified.
I will update my impressions from time to time.