In Kodak Xtol I had a development time of 40 mins @ 38 celsius at 1+1 dilution with intermittent agitations with great results (Superia Xtra 800 xpro to "E6" using Xtol as first dev and C41 as colour dev, works magic, also tried on Reala and Astia 100f with great results).

Anyway, ignore the fact that it's colour, and just abstract it.

Using the same film, I want to develop in 'Rodinal' R09, in 1+100 20c, (actually already developing a test roll of it with +/- 10 stops in 1 stop increments with it written on the subject in each frame to see how much the development is off), does anyone have a rough translation of these times/temp to this developer/time/temp I can use as a starting point to pull this out?