RE: Nosen P-51 flap modification
if i get what you are asking, check this out and try with some scrape first as i havent tried it this way but am 99% sure it will work for your needs.
the way i figure it this meathod should give you 30 - 45 degrees motion up and down allowing for 60 -90 total degrees i.e much more than what you need so this may be the easiest way with out buying those weird robar fouler flap hinge things.
please PM me if you ahve any other questions.