When you say you are a shower do you mean you never turtle? If you did an over intense workout and ran into a cold shower you would still be 6 inches flaccid? I was a total grower to start and now I’m usually no less than 4 inches nbp flaccid. Sometimes in a warm shower I have a much bigger flaccid. In 1 year, I’ve gained about .75 inches length, .25 mid girth and at least .5 base girth.
As for shower vs grower gains, I think if you are a big shower you probably have a lot of internal spongy material which may take more effort to stretch. Maybe a grower has less and relies entirely on blood for a hard erection. We should probably define shower and grower. Maybe a grower is one who doubles in size or more? I would like to see gains for showers and growers broken down too. It would be interesting.