Lee Wide Angle Adapters for 90mm and 75mm Grandagon-N

[JPlomley]

In order to combine a polarizer and GND filter, I was going to purchase the wide angle adapters from Lee in order to mount a two slot filter holder. The rear slot for the GND filer and the front slot for the 105mm polarizer filter (B+W warm tone). I don't believe this combination would vignette on the 90mm/4.5 Grandagon-N, but what about the 75mm Grandagon-N?

[JPlomley]

Anyone at all using this combination that would care to comment?