I use Hassey "F" lenses (fast 50mm, 110 etc. they are basically faster, and BIGGER than the 3.5 and f4 CF) with contax P45+ and MAM-1 a lot.
No issues, focus confirmation; you do need to get used to setting exposure
(but the contax does work pretty well once you get into range.
Of course, you need to get pretty good with focus with lomg lenses, but w MF you are always a litytle wider than with 135, so it isnt that difficule.
That said, The Contax lenses are damn good, and I rarely use the hassey's any more (except to play around) except for the 250 apo. THAT is really a speciall lens