Lee 77mm wide angle adapter for 100mm system, FS $42 shipped or prefer to trade for a 72 or 95mm.
Please take a look at my other junk for sale so I can then buy your junk (and I don't have to bump it)
Leica APO Extender R 2x
Markins M20 w/ Wimberley clamp, Black Exc+
plus a bunch of 35mm junk over on FM