A great deal has been written on this topic. Some of it very confusing to a darkroom worker like me, dedicated as I have always been to the KISS principle in my D&P.
You can easily and simply resolve this to satisfy yourself. Sacrifice one roll of your favorite 120 film (or a partial roll of 35mm). Shoot 12-16 exposures of the same scene at the same exposure, to ensure consistency.
Cut the film into two lengths. Process the first length with a 1-2 minute presoak, and the second length without the presoak. Compare the results.
If feeling particularly obsessive about all this, you can then repeat this experiment with a 10% or 15% reduction in developing time.
I did this testing regularly for a long time, with every new film I bought. Eventually I realised that with only two exceptions, there were no variations whatsoever in the prewet and not prewet films. The two exceptions were Fuji Acros and Ilford Pan F, which I have long regarded as "difficult" emulsions anyway.
Try this and you will then be satisfied with your own tested results, not someone else's developing charts.
I now use mostly D76 and Xtol, but I was a dedicated user of Thornton's Two Bath (the Ansel version) for many years, which by and large is not recommended for rotary processing. I did it very happily with my Dobo Duolabs for a long time, and found that adding 60-90 seconds to the developing time kicked up the shadow and mid tones contrast nicely. Unlike many others, I did not have any problems with "bromide drag" from the constant rotating. Others' mileage may differ in this. Those who would disagree, please let us know (and please tell us why).
