I have very squeaky - creaky hard wood 1/2" thick oak flooring in some areas, that I am about to refinish. In Short, my question:

Do Counter snap / break off head screws work?

Here is a site with all the info on them:
http://www.squeakyfloor.com/counter-snap/

My 2nd question is WHY have none of the 5 professional contractors who have been to my house and given me bids, not suggested using this technique to quiet my floors?

I had most contractors say to top nail it, one said glue it from the bottom, but not one said counter snap screw it, which looks to me like the best solution. I would think top nailing the floor with finish nails, would eventually in time end up doing the same thing it does now, move, and squeak and creak. Threaded screws though,, would hold until the wood rotted. Any thoughts?

Give 'em a try. When screws are used the portion going through the board being fastened is supposed to not be threaded to it and the head is what holds the board. These will have threads in the floor and subfloor. If the floor is not tight to the subfloor and these are used and the head is snapped off the only way to fix would be to drill the whole thing out. Although they would create slightly larger holes, trim head screws would allow removal and repositioning if necessary.

do you have access from below? if so you could use short screws and tighten it up. If its squeaks you may have more than the flooring flexing, could be in the subfloor or floor joist as well.

Anyone familiar with chevron floor installation.
Do the short sides which meet at the points need to be tongue and grooved by the mill. Is that a must?
I spoke to one large mill in Ohio that told they only set up the long sides for tongue and groove