Originally Posted by Fuji
Well from my experience, SS seems to raise the grip size by about a quarter, if that. It does compress down eventually to the proper grip size I find though. Obviously it's not going to be as compressed as leather, but it does settle in for the long haul once it does fully compress.
So in short, yes it does stay the same size (for me at least) and it takes about a week of hitting for me, which is usually around 10ish hours.
Now that I've been using Shock Shield for about a month, I can say I agree with you for the most part. At first I was bit concerned about the larger grip size, but now it feels normal sized and stays that way. I think the break-in period was less than 10 hours for me, probably 3-4 sets.
If you can endure the short break-in period, it's a very nice grip for dampening shock and vibration.