Just for those that are curious, here is what I came up with.

Start with the hard developer first. I used dektol. It needs to be strong 1:1 and 1:2 produced identical results. 1:5 did not produce full blacks.

Aim to be in the hard developer (dektol) for 5-10 seconds. You want to have moved to the soft developer (Selectol Soft) before the first blacks appear. I still saw full blacks at 5 seconds with dektol 1:1. The longer you stay in the hard developer the greater the effect it has on the midtones.

The second developer needs to be very dilute. Selectol Soft is normally mixed 1:1. I saw the best results at 1:9. I am going to experiment with even more dilute solutions next.

Expect longer overall developing times. My normal time is 2-3 minutes; however, with the really dilute (1:9) soft developer I would suggest starting with 5 minutes.