AFAIK, this was just a backup for the Burgundy/CAR Jackson. I think H got Dave in contact with Jackson before he left IM, because Dave at that point wanted to retire the Kossoff strat and Jackson were able to do copies of necks (H's Jackson neck is a 22 fret copy of his 1957 Stratocaster).
So in short, the specs should be Floyd, alder body and a maple neck based on the Kossoff strat. The pickups should be Duncan JB and 59/Jazz. However, from the photos, it seems like the white strat had Jackson pickups in it (as did Adrian's) or even DiMarzios. Bridge pickup was soon changed to a white humbucker. There is also a question of chicken or the egg... Which Strat was first, this one or the burgundy one, but considering the later was used on NPFTD, I'd guess the later and the white one was built for the tour as a backup. AFAIK, during NPFTD warm up gig, the 1964 Strat was used as a backup.