I tried this: (like in the Hutchings book on PMK) A bright light at the top of a long white sheet. Then I metered all the zones with my spot meter and placed circles where those zones were. I then shot three sheets for each film I was testing. Each sheet got a different development time. I then printed them all on #2 paper with the developer I will use and choose the print that got all the zones. That way I have the development time that goes with the complete combination. If the sheet with the correct span of zones looses zone 1, I know to lower the film speed and re-shoot. I found that manufacture specs usually print at N+1 on grade 2 paper. So I usually find that nearly 1/2 ISO film rating and 15% off development time is close to where I will end up for N processing. I don't have a densitometer. I could probably tweek this a little more - but I am very close.
The film speed is connected to the contrast compression and contraction you want. So to determine film speed without contrast at the same time will not really get you where you want to go.