Dave,
It is a real bugger to get those nuts on. Unfortunately Steve's wife Lulu was not available to help me so I resorted to duct tape and a openend wrench. I placed the nut in the openend wrench and put a piece of duct tape on the opposite side of the openend to hold the nut in the wrench. Then an assistant on the outside turned the bolt while I tried to get the nut positioned correctly and treaded, we managed to get everything bolted back in place. As I recall there were quite a few salty sailorly words spoken during the process.
Its been a number of years since I rebeded those stanchions, in recalling the adventure I think I may have put a slight bend in the openend wrench to aid in the process. I also remember a small mirror being used to look up into the bulwark.
Take a close look at the stanchions before your reinstall them, or better yet mark them before you remove them. There is a difference between the forward most and other stanchions. The forward most stanchion has a spacer welded into the base that moves the stanchion inboard slightly and keeps it upright rather than angling outboard.
This is also a good time to rebed your mooring cleats if they are mounted on the bulwarks.
Kevin