I would just toss in that you need to get accustomed to having your arms provide nearly all of the power and you need to get accustomed to gliding.
The basic stroke starts with a sweep that looks like you're flapping your wings, then as the arms pass below the shoulder, the hands pass at about a 45' angle, tracing a line that would pass through your shoulders and end up at the bottom of your rib-cage. At that point, the hands come together and you push them (one big "cup", thumbs together) straight down the midline. At about the waist, the hands part, so that once that stroke is done, your arms should be by your side and you just let it glide (body straight, head down, toes pointed, hands pinned against side like you're standing at attention), possibly extending the glide with a quick body-wave/dolphin kick.
Ultimately, everyone is different and they evolve variants of the stroke that work best for them, but getting a good glide and getting the number of strokes down to about 5 or 6 per 25yds seems to be almost universal. David Lee had a post where he said he was doing 3 strokes per 25 yards, but (if I read it correctly) he said that a slower approach that had about 5 yards per stroke seemed more efficient.
The biggest mistakes that I see people making when they first do no-fins is that they take too many strokes per lap (no glide) and they try to do big frog-kicks (which just slows you down) and they don't keep their head down (make yourself look at the tile and use the markings to let you know when you're near the wall).
The Topi and David Lee films are awesome as far as style, but I think that vertical no-fins is a bit different from horizontal -- you need a lot of power to get off the top and a lot to start up form the bottom, so those guys seem to use more leg at times than a horizontal swimmer would. David Lee did post some links a while back that show him doing some horizontal practice.
www.apneablue.com/videos/25m ucb pass1.wmv
www.apneablue.com/videos/25m ucb pass2.wmv
You gonna film this? I always love your photographs.