Upload & Sell: Off
Well, I dug out my B&W CP, regular thickness, and did a test. I hadn't tried it with the Lee filter holder before because the front ring of the CP was dented from a fall and wouldn't thread the Lee adapter ring. But after reading that some of you have been able to use a normal CP with the Lee, using a WA adapter, I was encouraged. With nothing else to do tonight, I used a hammer and a small metal rod to direct the blow, and managed to bang out the dent sufficiently for the CP to accept the Lee WA adapter. So I set it up; 17-40, B&W normal CP, Lee 77mm WA adapter, Lee holder (reduced to one slot) and GND.
The verdict: there is only a tiny, tiny vignette in a smidgen of the corners... negligible. It's from the WA ring, not the holder, so I could try adding a slot or two back, but I have no reason to because the GND filter is the only one I have or want to use in the Lee. Anyway, Whehoooo!!!! It is a little tricky to level the Lee w/ GND after the CP is set; I have to get the tip of my finger on the CP within the WA adapter, to keep the CP from tuning out of adjustment while I revolve the Lee stuff... but thats a small inconvenience to save the almost $400 it would cost to get a 105 MRC CP and the 105 ring.... Whehoooo!!!
Thanks everybody, for your comments on this arcane issue.