A strong power wash is essential is get a gauge of how bad it really is under there. IF you can get a power wash with hot steam use that before you start with your derusting. That will help a lot
Once all done and "coated" most of it 'drys' so its not any issue getting at stuff to repair. Your arms/clothes can get a black 'shine' but no bother.
Not sure how dry the WoolWax, Fluidfilm after some days. I can only compare to Waxoil that I used before and current Shultz I've used now.
Although, it's not really *power washing with steam*, I do have a Mcculloch canister steamer, and I can likely borrow a power washer, so I may try some combination of steam cleaning and power washing prior to de-rusting. Great advice - thanks!
Suj