Hi Steve
I took my rudder to bits. A lot of the bolts are difficult, John Bakers idea of antilock nuts was to hammer the ends.
I did paint the whole of the blade, it has worn quickly in the stock.
The inside of the stock, never painted, had only surface pitting.
I cleaned off the paint with stripper and an abrasive disc. I used polish before rebuilding and have applied spray silicon since.
Good luck
Philip