Just a couple of notes to clear up some confusion about mast position. If you're riding strapless, you have a lot more freedom to move the mast fore and aft. The limiting factor is related to getting up. If the mast is too far forward, you'll tend to pearl the board before you can get up. If the mast is too far aft, it will be hard to get up at all or ride in a balanced manner.
Changing mast position does not directly affect handling as the video a few posts up suggests. It will feel like it, but you need to understand what is really happening. Once you're up on the foil, the board has only one effect on handling: rotational moment of inertia. By moving the mast forward you reduce that moment by decreasing the radius of the mass. Reducing the radius reduces the rotational moment of inertia and improves your foil's handling. Great! One thing though, there's a lot better way to do that. Switch to a smaller board.
When you're learning, you need a bigger board to be able to get up easier. You can ride the board itself before engaging the foil. As an added bonus, that big board with lots of nose rocker makes recovering from touchdowns way easier. Having the mast further back on that big board puts more nose out front and puts your center of balance further back. This makes everything easier, but that big board is really slowing things down. Good for a beginner, less fun for the advanced. Going to a smaller board reduces the rotational moment WAY more than moving the mast forward on a big board. This will make the foil incredibly nimble and fun. Expert Kite foilers will use a board barely big enough for their feet!
Once you've mastered foiling on a big wake foil board--longer than four feet--try a smaller board. The Slingshot Dwarfcraft or Dwarfcraft Micro are excellent boards to try. (They're in the kite foiling section of the web page.) These are NOT good boards to learn on. You'll most likely just get frustrated trying to learn on one of these. But once you can ride the foil at will and not touch down unintentionally, you'll literally be amazed at the difference in your riding.
EDITED TO ADD: Sorry, I forgot there were two different Dwarfcraft sizes. I'm talking about the 3'6" version here. the 4'6" one is still a big board. The 3'6" one is a medium sized board. 3' and smaller are "pocket" boards. Small enough to fit in your pocket, LOL.