Very nice work kazooplayer! My hat’s off to you for your dedication.
My theory is that all factors held constant, the time required per incremental gain is an exponential function. I think if you allow yourself a long break, you may be able to speed the rate of gains for a time once you restart. I’m talking about a 6 month (or longer) break, not a couple of weeks. I’m testing the theory, now. Well, kind of - my break was more like 2 years. The idea is to erase your body’s protective measures that have created resistance to the strain.
During my break, I lost almost all of my 1/4” girth gain as fast as I acquired it, but didn’t lose any of my 5/8” length gain. It leads me to believe that rapid length gains are a more permanent phenomenon than rapid girth gains, but I don’t think that this is the case for long-term gains. I only gained 1/4” to your 0.8” and over 4 months as opposed to 2.5 years, so I would hope that most of your gains are more permanent than mine were. Fortunately, it seems to be coming back faster than I originally gained it.
I would be extremely curious to see how much you lose and how quickly. I’m also curious about your routine and how regularly you tracked your gains. My projections for gaining 0.8” girth are about 3 years, which is pretty close to how long it has taken you. The difference may be that I started at about 6” girth. What girth did you start at?
In summary, you should expect to lose some girth, but I would expect (hope) that you will keep most of it just because you’ve had it for so long. This isn’t based as much on my brief experience as 6 years of reading in the forum, and paying close attention to the guys that provide a lot of data.