More time is always going to be better. In my opinion, the reason why some guys like BIB have great gains, is because they did hanging literally ALL DAY, every day. He worked from home, and would hang for his entire work day, non-stop.
The penis muscles, if you even want to call them muscles, need to be stretched out for long periods of time. It is during the time they are being stretched that the growth will occur. This is different than training other muscles, like your biceps, which actually grow while your outside the gym. Smooth muscle tissue is different.
Before moving up in weight, make sure you are going for the full length you possibly can.
If you are able to hang all day, then hang all day.
Just dont sacrifice your work efficiency, mental health, or relationships for it.