Is the f-one release usable with either hand within parts of a second?
No, if you read my initial post, I say that I would like chickenloop with two pull releases, one on each side of the loop. And as I mentioned, I don't think the F-one release is "good", I just used it as an example of a pull release which works even if the lines are slack.
In general, the "accessible from two sides argument" is the only argument in favour of the push release that I really accept. Ordinary pull releases are one sided which is bad.
For people who ride hooked in all the time (90%) a one sided release is not such an issue if you remember to hook in the same way each time. However, sometimes you do hook in opposite to your normal direction, and here a double sided release would be good.
I once made some preliminary designs of a chickenloop with two releases, one on each side of the loop. The main advantage was that no matter which way you hooked in, you could release from either the left or the right side of the loop. You could also release with the lines slack or tensioned since you pulled perpendicular to the lines. Furthermore, if you were unlucky enough to get sand in the loop and the one release was jammed, you would get a second chance with the other release. In all current releases, you only have a single release. If your chickenloop for some reason gets jammed, you are in for a wild ride...
I have to see if I can find some of my old drawings.
As mentioned, I am not saying the old pull releases were good, I am just saying that the current trend to only support development of push releases is wrong. Push releases have a fatal flaw which is that it is difficult to release them if you are being pulled by your kite at high speed along the ground or even possibly through the water.
By the way, I should mention that I have been involved in both Ozone, Fone and Flysurfer, so I have experiences with both pull and push releases. Of all the releases I have used, my personal favorite is the old Flysurfer pin release with the big red ball you could pull on. This release was impossible to jam with sand, was very easy to grab and pull even with heavy gloves on, you could release with slack lines and you never every released it accidentally. The problems with it were that it was a pain to assemble if you did release, it was necessary to activate once in a while so that the parts didn't get stiff over time and it was only accessible from one side.