But still, there is only a small zone in which going faster VMC first would not be best. On a short leg, it's a coin toss. If you will be carrying the spinnaker on the NEXT leg, you may want to sail high first, then set. You will already have your chute up for the next leg. If you sail low with chute first, you will have to douse and re-set which gives you an extra chance to screw up on boathandling.
Spinnakers vary widely in shape.
You should continue to experiment with pole height. This also moves the sail more out in front of the boat, reducing heel and weather helm. Some people commented that the boat felt better with the pole on the headstay rather than back several feet. As a general guide, the pole should be oversquared approx. 10-15 o on a tight reach.