Understandable Rob, I was just teasing..
On an interesting note, you make mention of value once again.
I suppose it comes back to the "rare" versus "valuable" arguement.
In this case, 6 or 7 oddball prototype vehicles would definately fit into the category of "special". Only the most devouted and true purist would take on such a beast, with it's unique design and questionable parts availability.
As they were custom one-offs, surely many of the components would be hand made (body, frame etc)
A fellow such as yourself would fit the bill of course, with capable hands to make things work or jury rig to suit as the situation may entail...
Back to the question of tires, I assume that these prototypes came with manuals and spec sheets, surely correct tire designation should be easy to find?