I would think you would need to build up the inside somehow, maybe by mixing saw dust with the glue.

My experience with roller-ski tips that are not the EXACT size (much less than 7-vs-10 mm) is that I need to use epoxy gel, otherwise they would come off rather quickly the first time out on the trail. BTW, I don't have any major trouble getting them off -- using a heat gun, however, to soften the epoxy.