I've been hanging with a vacuum for 2 months. I increase the weight every 2 weeks. I'm currently hanging with 6lbs for 3 x 20 minutes. It's been 2 months but no gain. At what weight do the gains start?
In most cases people report gains at around 8 to 10 lbs, for some it may take more weight. The toughness of your tunica will determine when you gain and at what weight.
The early stages should not be rushed though. This is very important for conditioning.
I'd figure a few months of consistent and proper hanging to get to the gaining part. Also, gains do not come fast with hanging.
You can incorporate some manual stretching along with your hanging routine.
Don't measure too frequently, it can be discouraging.
If you only gain 1/16th of an inch a month, that would be 1/2 of in inch in 8 months. 1/8th of an inch a month would be 1/2 of an inch in 4 months.
To achieve the easiest gains, try and hang BTC to deform your suspensory ligament.