I tend to drop a couple through the .691 insert and have found that it's usually one either side of that depending upon the brand. If they fall through I go down a size, anything more than the weight or another ball or two not being enough to push them through I go up a size.Are you being completely honest Nige???
I have never found that accuracy has been bad from having too BIG a barrel size. But obviously a too smaller barrell size will just mince your balls I use the blowing technique just to be safe....... It dosn't take an hour more like less than a minute!