'Lb's of pressure taken when the boat hits.' It seems that that can be very high, depending on skier weight, amount of rope slack, boat speed, etc.
For Gs, it depends on are you talking about average sustaining or peak. Both are relative short duration, and of course peak is very short. So from observations, it seems 1.5 to 2 for sustaining and 3 to 4 for peak are reasonable.