First, I agree with BigO that manual stretching along with pumping is a good idea.
I completely packed my first 1.5 inch cylinder after about 9 months of pumping. I am currently packing about 3/4 of the way up my 1.75" cylinder.
During the first two years I alternated between two 20 minute sessions at 5 hg(one in the morning and one before going to bed) and three 10 minute sessions separated by Ulis (in the morning and again at night). However, I would (about twice a month) do a 30 t0 45 minute session at 4 hg. I rested one or two days a week.
For the past year, I have reduced my routine to only one session a day.
I also use an extender two to three hours a day, six days a week.
I jelq and stretch at night in bed for about 30 minutes before going to sleep