We plan to add tabs on my 40. The roof and side pillars have a tendency to sag over time. You will first notice when you try to add the windscreen. The corners of the roof are also where people will try to grab on entry and especially on exit. Press down on that area and you will see how weak that area is. The roof looks for strength with the windscreen which is not a good idea. The tabs will keep all aligned(once aligned). 3M has some great adhesives that will tear out the metal before releasing. Their bond times are variable depending on which one you get, so there is plenty of work time with them.
Bill