I would suggest that there is a little more humiliation ahead of you
From my experience (and from other racers I have discussed this with), I would say that it usually takes at least 20 hours on a new race board before becoming comfortable. The more time you spend on it, the more competent you become.
I also have the Monaro V4 and am loving it. It took more like 2 hours than 20 to get used to and is by far the best board i have had. However, I have been riding race boards for 3 years or so. Stick with it and you will get it.
One point to make, is that it probably won't like riding on its windward edge as much as the Sector does. Coming from a twin tip background, I initially found it a challenge to ride a board flat, let alone on the leeward side. So I would concentrate initially on trying to ride the board as flat as possible.
Beyond that, I guess the main thing is practice. You will probably end up drinking a fair bit of river water (as I did), but after a while it will begin to be worth it