my 5 has2 or 3 mast positions,slightly forward for walyungup and back for lefroy.
that was set up for4.00x8 wheels
having said that, when i changed to 26" wheelsI moved my weight back by 150mm without and detrment on walyungup. probably could have moved the mast back too but ran out of time to test.
note I didnt change the mast angle ,just the position
the boom when sheeted in fully is parallel to ground and 500mm above.
your job is to make you and the yacht fit under that