Thanks for the useful and interesting information. I have tried some 35mm at 1:50 for 11.5 minutes and felt had more grain and was less sharp than I would expect from Acros but I did wonder If I was just expecting too much from 35mm having been used to 120.
I will try 35mm at 1:100 for 18 minutes at 20 deg C) as I do for 120 and see how that goes.