The way Barnbaum does it is to move the center part of the exposure up the curve. This way the lower zones don't get all muddled up on the toe.
As an example he uses Tri-X 320. He rates it at 160asa and then exposes shadows for zone 4. Effectively he is rating the film at 80asa with a zone 3 shadow placement. To develop he takes his HC-110 stock solution (mixed at 1:31) and then further cuts it 1:7. I don't have the developing times with me as I'm at work, but if anyone is interested I could give them to you.
He regularly gets way more than 10 zones of printable information on the negative if the scene yields it. Naturally he uses N + or - when needed.
His buddy Don Kirby uses TMAX 100. Rates it at 100asa and develops in Xtol. I also have the times for this as well if you want. Both of them get outstanding negs.
Both of them come from a scientific background and neither of them have any use for densitometers.