Personally, I wouldn't even consider a 35mm DSLR lens unless it is AF. I sometimes shoot for 10 straight hours and about 7 hours into such a shoot the eye fatigue starts making manual focusing lenses pretty damned difficult ... except Leica M rangefinders for some reason.
I know all about the Canon 85/1.2 in both the first version and so called faster MK-II version. Shot for years with both. Turtle slow AF in low contrast, dim light ... mostly solved by using the Canon STE-2 Transmitter which puts out a good focusing pattern target on the subject.
The Zeiss ZA 50/1.4 doesn't seem to suffer from "Turtle Syndrome", so I'll bide my time and wait for a ZA 35/1.4 if it ever comes.
BTW, if I rent anything to try it'll be the new Leica S45 ASPH ... which is the same FOV as a 35mm in the smaller 135 formats.