Whooooooo - off thread but very interesting. (I hope. Haven't looked at it yet :-}). Should be added to useful links, I suggest?
Good to hear you are making progress Gary. I was about to suggest drilling the hole oversize, but David beat me to it. I always use that method, not in the least because it's the only way I could ever get anything to more-or-less line up, because both my hand to eye co-ordination and measuring abilities leave a lot to be desired.