Re: nut size
If yours is like the old one I had on my 35 it is plastic and can and should be loosened and tightened by hand. Then it gets locked in place with a tie. If it's bronze you can loosen and tighten with an adjustable wrench which I would carry on-board. It isn't necessary the make the lock nut all that tight, just dab a little silicon on the threads to secure it and make for much easier adjustment next time.