After talking with Brian at CTI, the plan is what alot of you have suggested. Peel and glue. The problem is half liner, and half over sized grains. The liner should be 2.559 with .004 tolerance plus or minus. My liner is 2.550. My grains are about .008 to .010 bigger than the grains Brian mic of same motor White propellant 75mm still at CTI. He likes sanding over peeling because sometimes when you peel it comes off thin in one area and thick in another. This unevenness could cause trouble with flame on back side. It would take too much sanding to take off .010 by hand. So the game plan is peel, sand a little to make sure it slides in liner nicely, then glue them in place. The glue will fill any voids on back side if it did not peel evenly. He doesn't recommend freezing the grains because of different expand contract ratios between the casting tube and the propellant which might cause unwanted stress on grain and small cracks develope. I know others have problems with CTI and the G78BS. In my experience with Brian and CTI, he called me back two days in a row and talked for 45 min each time. He answered every question I had and then some. He was very professional and I feel he did a great job telling me my options and what to do. When they matched what you guys have already said, I knew I was on the right track. Its not that I don't believe you guys, because I very much trust your expertise in these matters, I just wanted to here it from Brian and CTI. If I didn't respect you guys advise, I wouldn't be here!