1) The Naylor Observatory has Bortle 5 skies, more or less, but light pollution has been getting progressively worse with each passing year.
2) I assume that the 17" classical Cassegrain has at least 1/8th wave optics. It was built by Mike Dudley of D & G Optical back in the late 1980s I believe.
3) I have not and I don't know if one has ever been done.
4) I've tried to resolve the Vallis Alpes rille a number of times but have never been successful.
Thanks so much for your responses Dave! FWIW, I myself have been only able to detect fleeting ‘albedo’ artifacts of the VA rille @ 451X with the C8-A + TV4.5D (under Avg+ seeing with VG+ transparency). I’m trying for Armstrong, Collins and Aldrin (along with the Vallis Alpes rille) when I get those 1-2 nights/summer of excellent conditions here in Chicago or at my dark skies Lake Home...
Clear, steady nights.