Just a follow up on this. I wasn't happy with the aftermarket fan clutch setup - still seemed too loud. Finally got around to looking at a neighbors disco and my fan was backwards (in other words it was fine the first time). Being tired of the whole issue I ordered a fan clutch and new fan from Trevor at RovaFarm.com on Thursday and they arrived this afternoon so I threw it on. No interference.
So I guess my enlarging the holes or some other other difference in the fan clutch was responsible for the interference. Probably would have been fine just trimming the blades. Of course I forgot to compare the two again before installing.
My cheap bastardness burnt me this time
But I guess now I have a spare (with a lifetime warranty). Just might need to trim it.