I think you are taking the post too literally. In my experience, make an offer. You could get a response in a day or a week, or even longer. But, make an offer. You can always raise it later, even if they don't respond to the first.

I've used some of the domain negotiating services, though only for private domains. You can always make a direct offer to the private registration companies, if you don't want to go the negotiator route.

In my experience, you just have to start the process w/ a serious offer. You have a pretty good starting point w/ Brad Feld's blog, so a 1-2k offer is as good a place as any to start.

On the flip side, start with the highest number that if someone offered to sell you the domain at that price, you'd buy it as a no brainer. Best of luck.