Clutch disk and pilot bushing do not correlate.That is really why I'm looking into the disc thickness. If the thicknesses are the same or close enough, then there are plenty of 10 spline, 9" Ford clutch discs out there that would work with the later V6 Ford T5's (like Zippy used), the S10 pressure plate and AL flyhweel.
You have to change the pilot bushing if you use some of the earlier ones prior to 2005 (V6 or V8) and the adapter plate thickness changes with the particular T5 flavor.
And it may be possible to change the input shaft in most of the Ford T5's with the 14 spline GM one, which you can buy for <$60. But it may involve some syncrho changes in some. I think someone is looking into that.