You guys mean CO2 buildup, right? It's O2 that gets consumed. Anyway, both of you do have a very valid point, since more efficient finning techniques and hydrodynamics can help us to reduce CO2 buildup and oxygen consumption. Hope you don't mind if I humbly chime in with a few observations and some tips that work for me.
Finsailor, keep on trying out those different variations until you find one that works for you. I tend to use a technique very similar to the one described by neurodoc, though I used to be a kick-and-glide guy before. I incorporate ankle flicks into my monofinning motion and I remember that when I tried the Lunocet classic a year ago I was impressed by the fact that it allowed me to do 50 metres using just ankle flicks and nothing more. The problem, however, was that no matter what technique I used with it, I could never get past 60 metres. Nowadays, I don't train with a big monofin as often as I do with a Finis Foil training mono, which is very soft, so you get a lot more out of those ankle flicks.
Neurodoc, I like your description of how the Lunocet Pro works for you. That's what I'm betting on for when I get mine, since I generally have a better disposition towards static apnea than dynamic. I get farther across the pool when I use a "lazy" technique - that is, I relax and move slowly while maintaining a hydrodynamic form - kind of like a moving static, if you'll permit the oxymoron. This, of course, is helped along by a triathlon suit that is weighted at the neck and the sacrum.
Speaking of hydrodynamic form, I can see why the idea of a pec fin, or something to stabilize the hands and upper body, would be appealing to many of those posting here. I've been enjoying the videos too, though I wonder about what problems it might pose for turning at the wall. Personally, I'm more into just cultivating core stability and streamlined position by practising undulation on the surface with a frontal snorkel, working with the line of the water's surface and then applying that sensitivity underwater.
This is not to say that using a fin for the hands or pecs to keep a straight line won't work for some people, so let me offer just a few thoughts on the subject, whether one wants to cultivate the habit of streamlining their body, or use a hand/pec fin a little better. I sometimes train with a Finis Alignment Kickboard (and no I'm not a spokesperson for Finis) when undulating at the surface with a frontal snorkel. It has a bit less buoyancy than a regular kickboard, so it stays just a little below the waterline. The strap on the top of it keeps your hands in place, and you can practise your hand position that way too. This could be helpful for using a hand-held fin, or the pec fin in the video above. It might give the impression of cutting through the water and creating stability for a swimmer, but it does not guarantee a streamlined position. I also squeeze my head lightly between my biceps, just at the backs of my ears, to take some weight off of my shoulders when using a monofin or bi-fins in dynamic apnea, and sometimes I wear two swim caps to make the traction between my biceps easier. This technique could also make the use of a pec or hand fin more stable.
