Originally posted by markp27
I get a flat piece of solder measuring approx 0.2mm - but don't you think then that 0.2mm of shims would be too little?
I will try it, though - I'll richen the bottom end and try 0.3mm of shims first of all. Then, I'll see how it responds.
If I've understood correctly, the engine will run hotter with fewer shims.
BTW: The blown plug the wire was sticking out, so this should mean too many shims. Next time I hope it runs better 
Yep. This is correct. I just noticed a typo in my first post. We actually started at 0.4mm and went to 0.3mm with 16%. blown plug with wire sticking out would suggest a couple of things.
If it was pulling out previous to blowing you have too many shims in and if the plug blew without breaking the coil inside it would suggest too lean on LSN.