Hi. I assume you have looked at the Soul user manual (https://flysurfer.com/files/dlm_uploads ... ual-EN.pdf
). It talks about the effect of the PMA adjustments. If I remember correctly I think people on the massive Flysurfer Soul thread suggested just making a change to only one or two of the outer wing tip PMAs (and Armin also made a few suggestions about stability) but the guy on this thread here (https://www.seabreeze.com.au/forums/Kit ... erformance
) changed each one. You will note that he wanted a higher boosting kite at the expense of stability. Don't forget that the 9m soul has slightly different characteristics to the 10m due to its different aspect ratio.
The second point is that you can't really adjust for BOTH better boosting and stability together. You kind of have to pick one or the other. As it is, I would have expected the 9m with its lower aspect ratio to be more stable than the 10m in gusty winds but gusty winds are pretty rubbish to kite in regardless of kite.
As I understand it, the advantage of the PMA over bridle changes are that the PMA adjustment changes the aerofoil shape throughout the entire bar stroke rather than just at full power. Foilholio explained is on one of the pansh threads if I remember correctly.
Not sure how experienced with foil kites you are but I have found its worth checking a mixer multiple times. I've been known to do a mixer test, then check it again the next day and be amazed how far out it is on one side or the other.
Hope this might help