I'm not Steve. As a matter of fact, I wouldn't make a wart on Steves neck, but I might can offer some help.
Yes, the fan clutch must be in good shape and will probably be more important for this than the aux fans. The aux fan is triggered to bring down high side pressure to prevent system damage, not necessarily to aid in the a/c system operation.
As Rolf said, the a/c in these cars are marginal in capacity at best. Since you lose about 20% of system capacity when changing to 134 you are on the edge of adequacy. If the conversion is not done correctly, the loss in capacity will be even worse.
There are different pressure switches available for 134 use. This will change the cutout pressures to be more favorable for 134 use. Since I have never converted a 201 or 124 car due to their marginal capacity, I don't know where to get such switches.
If the car were mine, I would thoroughly flush the system, replace the filter drier, dump as much oil as I could from the compressor, pour some mineral oil in the compressor, turn it a few rotations and pour it out, then put in the correct amount of mineral oil, evacuate and charge with R12. In other words, clean up the system and reverse convert.
You very easily could end up spending more time, money and frustration trying to get the system to perform to your satisfaction with 134.
I've seen a number of 134 conversions that were done at greater expense and trouble than simply repairing and staying with R12. All that is done and the system has no chance to cool as well as it did with R12.
Best of luck,