When I put the first strip upright at the front, it seemed to be correctly located.
I continued around the front of the cockpit curve as shown in Nick's video.
It appeared that you could just clamp the next strip to the first and just go around to the sides, and the strips would be vertical.
Somewhere I screwed it up, when I got to the side the strips were leaning out at ~ 30 degrees. After getting 70% of one side done I decided that was not going to work (I'm not real quick).
I took off the side, cleaned up the joint and re-glued the side vertical. It was necessary to lay a board across the cockpit opening to establish a horizontal, then I used a small square to set vertical.

So then I tried adding singles from the side until I got to the front centerline. This time the front was ~ 30% from vertical, leaning forward. I made the same error, going the opposite direction.

So I pulled off the front curve, cleaned up the joint again.

This time I glued up the front centerline strip vertical by itself (a single piece).

I built the opposite side to a vertical the same way as before.

Now I had two sides vertical, and one centerline stick vertical.
Out of my junk pile I picked up a 1/16" x1/4 strip, clamped it to each side and the centerline single stick.
Looking from on top the 1/16 strip had to be adjusted to hang vertically over the front cut.

Then I glued single sticks to the coaming cutout, leaning on the 1/16 stick which established vertical. This way if there was any adjustment to keep vertical, it was automatic and such a small adjustment with each stick that I got a smooth curve.
I did the same to the back.
Sanded out the outside face of the verticals, applied a fillet (the size of a tounge depressor, cleaned up the surface and glassed with 6oz.

This probably just shows how poorly I understood the video, I would appreciate Nick telling us how I messed up.

But, the vertical is done, reasonably vertical and awaiting cutting the strips for the flange.

Too much talk, basically the 1/16 strip was just a guide.