Back to this again - I was measuring the wrong place. It is exactly where Carson spotted it on the latest picture but I say with some confidence that it isn't even possible to measure the clutch on this particular setup. The gap is actually inside the outer diameter of the pulley. You would need a crooked, perfectly custom designed gap tool to have chance of an accurate measurement. Turns out it is a Nippo 17 but seems to have some sort of an unusual clutch.

The good news is that adjusting the gap is quite easy but that does not seem to be the problem as I played around with the gap and couldn't get it to work. The other strange thing about this clutch is that it has no pin holes for a pin wrench. But I found that an oil filter wrench/tongs worked just fine for locking the wheel as there's only 12 lbs of torque on the center bolt.

I also found that shims are not easy to come by. Two dealers had no idea what I was talking about. Several retail stores also clueless. Finally found some shims at an AC rebuild shop. I went looking for them thinking that adding shims was required to reduce the gap - as I read in a post here somewhere - but indeed the truth is the more intuitive approach - removing shims reduces the gap. It is good to have shims of various sizes for flexibility however.

So still no clutch engagement - seemingly down to two possibilities: 1) clutch coil problem, and 2) leaking front seal, which according another post here can cause the clutch to somehow slip on the shaft. I did see some evidence of a green liquid, presumably freon, when the clutch was out.