I started wave riding back foot out too, but both feet in the straps really extends the whole experience.
Agree, rear strap loose, and or offset it if your board has that setup.
Try leaning forward and pulling down on the boom, feels awkward at first.
Putting the mast foot forward can help in the early stages, but move it back as you get better at distributing your weight forward, and keeping the board on the plane throughout the bottom turn.
Setting up the bottom turn and getting that leeward rail buried/set properly is the key, and you can do it with more confidence with both feet in the straps.
Always look where you want to go and the rest will follow.
My lightwind setup, very easy to ride in the straps with its big/step tail.