I never measured the real head clearance before. But this is what i did. I put the piston at top dead center. Then rested the caliper on top the sleeve. And measured the distance to the piston. Then i did the same for under the head button to the glowplug.
I got 0.32mm and 0.36mm respectively. Is that good or bad? And this is not including the 0.3 mm shims.