All good suggestions, mikerb.
But it can change rapidly when the wind strength changes.
I was yesterday on my IS122 + 7.8 sail and felt a bit uncomfortable, the first hour when I was heavily overpowered also because of nasty chop.
I know my equipment + settings very well.
Then after 1 hour, the wind dropped off a little bit and I felt totally ballanced, without having changed any setting.
When the wind decreased further, there was again no perfect ballance and I also recognize the things that the topic starter describes. Too much pressure on the backfoot and difficult pointing. I always try to compensate this by turning/rotating my feet and body towards the nose of the board. It helps to a certain extent. But it remains a fact that Isonics like a lot of sail power and when you don't have enough of it, it's difficult tuning.
I experience this also much less on my IS101 (97) and IS87, but I think it is because I ride these boards in much more wind.
IS87 / IS101 / IS122 / US147