If you'll indulge me a shade further, then there are a couple of things that, although not answering the original post, dovetail neatly into it. Then I'll leave the thread to those better informed.
This may be obvious to most, but we've all come across engines that "like" to run rich. They produce a tad more power, but live longer than if they are tuned close to correct a/f. I think in most cases that the bulk of the charge (the combusted bit) is not that far off correct a/f (for max power), but seem to be running richer due to the uncombusted "quench" portions. Leaning them out can lead to problems, and detonation.
Secondly, the whole debate about " grooves" in the quench area I find fascinating. The thrust of the argument, and correct me if I'm wrong, seems to be the visualisation of "jets" of mixture being forced into the main chamber cavity, creating swirl and allowing more complete combustion. I don't discount this but I think there maybe more going on. I think that the channels created may be allowing a combustion path into the quench area that might not otherwise exist, a dendritic structure, allowing general combustion in the quench area, that might not otherwise take place. Somenders testing seems to indicate that the greatest improvements (mainly bsfc) occur in modern side valve engines, which now have some of the largest quench areas of modern engines.
Also the translation to other engines has thrown up interesting results; no real power gains but other improvements. If I've read right then the best results are gained by not having too tight a quench, and not too small a groove (automotivebreath I think), when if you wanted maximum charge transfer/swirl you'd want the opposite. Also if you look at the chambers of engines so modified there are virtually no carbon deposits (in the quench area, where you'd expect them) so you're getting a complete burn. The relative size of the groove/quench area must be allowing this to occur. Idle quality (especially) with bigger cams is also improved, so the exhaust gas diluted mixture can now support combustion. Reports of civlised idle rpms with some fairly hairy cams are common. Why I'm not quite sure, but maybe you have a localised richness in the grooves allowing peripheral combustion, like the concept of the Honda CVCC. Maybe it's simply a critical mass situation at work; theres now enough mixture to support a burn.
Supression of detonation, by allowing a more complete burn, is also probably occuring. I think even quench heads may be subject, on occasion, to a dgree of ping.
Sorry about the length, and if any of this has been covered before, but I havn't read it. They are just opinions/theories so as always, feel free to disagree.
"If an honest man is wrong, after demonstrating that he is wrong, he either stops being wrong or he stops being honest." Anon