A bit funny me making suggestions to you given you have taught me most of what I know

- but, I find the way that works best for me is to put the board on top of my arms for at least the start. ie sit it across the top of your arms with an edge under your chin. Both hands are then on the bar.
Works a treat for me and once up and going you can do what you want with one hand.
Generally is easy enough (although a little awkward) to keep it there once going but often once you start driving upwind with it you may need to hold it to stop it flipping up into your face.
EDIT: It has to be straps down too or it is too difficult to grab the board once you are up and let go of the bar.