Where are you located in Michigan? If you're close to one or more members it might be possible to pool a bit of knowledge, parts and experience and get you on track.
With respect to that, I can provide you with a CD that includes all the factory manuals (Parts, Service, Owner's), a wide range of How-To instructions, Pete Roper's big block engine rebuild procedure, period advertisements, brochures, wiring diagrams and much more; all specific to the 850-T model. Just send me a PM with your full mailing address and I'll drop the CD in the mail. No cost.
The same offer applies to any other WildGuzzi member. I have compiled model-specific CDs for most of the big block Guzzi models from mid-1970s to later 1990s. Again, just send me a PM with your mailing address and let me know which CD(s) you'd like. Shipped free worldwide.