Yes, you need to try and see which side of the pin is tight when the rig is under tension (get someone to slowly apply the highfield lever whilst you jiggle the pin) and adjust the position of the mast step. However, it is not that easy, since you need to check the rake of the mast (23’6″ from top to track at stern – or where the track would have been if you don’t have one) – all the measurements are dependent on each other.
The loose pin is important as the mast can fail at this point if too much tension. Have a look at some of the tuning guides on the website – even though intended for racers, the data is valid for all and a correctly set up boat is just so much nicer to sail………