Don't really have a strict routine to be honest. Just clamp as often as I can, anything between 2-5 times a week. Taking breaks for similar times to allow a bit of recovery. Usually clamp for about 30 mins never much longer as i dont want to do any damage. Using plenty of moisturiser for the skin asit get cracked and dry due to stretching.
I'm not sure the exact gains in but its at least 1/4" both soft and hard. My soft girth is now about 6.25", quite a bit thicker than before as you can see below
No gains in length at all though, I'm still only 8". Hopefully if I keep it up I'll reach the holy grail of 8x8