After using my Versalab for 10+ years with many lenses, I can assure you that the front ring of the enlarging lens is a good indicator of the lens elements. If that is way off, something is quite off and either the lens has been incorrectly rebuilt or there is something off on the enlarger. I have and align my Bessler MX45 and Leica Focomat 1c as well as other friends. I've also thought that the rubber band thing is not that good but after 10 years I've not thought of a better way. I actually just do a quicky check by holding the glass slide against the lens each and every time I print, my Bessler lens board mount has a small hitch and it can be slightly off when I change lenses for a format change. Last year I changed my first set of batteries BTW, and the Versalab would be the 1st thing I'd re-purchased if I lost or broke mine, works amazing for quick copy work as well.