Hi Lew,
As a sidenote, GMP and I are both very well qualified engineers as well...
You have stated as fact that the bushing being tight on the land will cause binding in this fork. This is not fact; It is your opinion and is not supported by reported experiences with this fork. (e.g. it is very plush when revalved and not spikey in any way, shape or form).
By the way, I spoke to Les at LTR and he said nearly all the marzocchi forks he sees have this bushing fitting tight, but that's it not an issue on this fork due to this fork having more than sufficient overlap. (He services and revalves 5-10 sets of marzocchis every week and has been doing so for the last several years...)
I have personal experience with 5 sets of the marzocchi shiver fork - three of them are cannondale surplus stock. The ones on my XR have tight fitting bushings and I am amazed at how good they are, even with very little break in time on them. I am an A rider with 35 years of riding experience and I ride very aggressively through roots, rocks and whoops; I can confidently say that if they had any issue - I would feel it...
This is kind of like a guy going into a doctor's office for their annual checkup and having the physician tell him that his knee has an issue that is causing severe pain; Performing a knee-ectomy will resolve the issue. Given that we are all human - some folks would immediately feel this pain and request to have their knee hacked off. Hopefully, a large percentage would say "my knee doesn't hurt" and spend the rest of their day looking for a new doctor...
jeff