And, since you mention it, that was another of Gary's ponts . . . OEM pads are indeed sintered plate, which is why the rotors develop the lines they do - so there wasn't going to be much difference netween the OEMs and the Carbone Loraine pads, which are also sintered.
As to fitting the shims, I did do a trial fit on one caliper (before realised just how much pad I had left and buttoned it all back up) and they fit fine. Perhaps the no name pads you can buy on Ebay have strangely formed backs?
Obviously, to each his own - but I suspect that no matter how one goes about it, since we don't turn the disks on our bike disks, replacement pads will always have some bedding issues no matter who supplies them.