It is a good idea to run one extra thin shim while breaking in the engine. While you would want to measure the deck height to be absolutely accurate (I never have with my engines), the extra shim will make the engine idle better, tune a little easier and be geaier on the internals during break-in. Most engines run fine on 30% out of the box and this one probably does too. I would shoot an email over to the engine's distributor to be sure.
"I have no idea what you're talking about, so here's a bunny with a pancake on it's head."
In mind and body, we're all heading towards old age. It is slower to go by bike.