On the matter of other clutches fitting, note that some engines have fans that spin the other way. The M103 is one such engine. I don't know if clutches are directional but if they are then M103 clutches are ones to avoid.

One thing I considered was going with an electric puller fan. There's not a lot of positive sentiment around that idea but I don't think very many have actually done it. Maybe the compromise is to fit the electric clutch from a 190E 2.3. Dave can probably find one for you in one of his scavenger hunts

Sixto