I will soon strated developing 8x10 negatives. Although I have a Jobo tank, I would like to start tray developing . I am a bit confused how many trays I will need for "mass" developing of 20-30 negatives in one session. Note that I am planning to have a Paterson washer so I will nee suggestions only for the pre-washing, developing, stopping and fixing. Plus I would like to know the size of the trys and the liquid content I shall use.