The use of Selectol Soft was as a substitute for having to mix the Beers Formula developers.
I used to use Dektol (or Ektanol liquid) 2:1 in one tray and Selectol soft 1:1 in another tray. The print would start in the Selectol for 2 minutes until I had a "full print" and then I would transfer it to a water bath to wash the Selectol off the print. Then into the Dektol for 30 seconds to 1 minute until the blacks looked solid but the shadows weren't blocked.
I haven't looked at the Photographer's Formulary website, but it wouldn't surprise me to find that they had formulated a replacement for Selectol Soft. Perhaps someone who does more B&W than I do now would know off-hand.
In any event, you certainly could formulate Selectol Soft or the Beers Developers from standard photo chemicals available from Photographer's Formulary.
The advice to use Amidol is also very good as it is a long scale developer and can be used quite successfully with graded paper. I've never used it with variable contrast paper and can't tell you how well it works with a dual emulsion paper.
Again, maybe someone else like Ed Buffaloe would have some experience with Amidol and variable contrast paper.