Any preferred manufacturing for shingle over vents? In my attic, once R60 insulation is put in and the fact that the rafters are notched to top beam, there will not be any air space for soffic ventilation. We are looking at shingle over vents for proper attic ventilation. Thanks in advance, Ian.

If you mean a ridge vent. Each line of shingle usually includes matching ridge material that will work. I am not a fan of asphalt shingles.

I believe that here is an example. IMO, over-roofing plus these allows any roof design to be somewhat vented (usually the best option in terms of moisture management). Also, over-roofing doesn't require two layers of OSB (the bottom layer can be rigid foam).