I'm not so sure a couple thou makes all that much diff if you are talking piston to head deck clearance .Besides that it's unlikely that using soft solder as a gauge and a set of micrometers than any two people would come up with the same measurements .
Then you get to talking about pop ups and you get 40 thousand opinions on how to do it,what shape ,how high ,what angle and how wide .Then it comes down to opinions and everybody is right or claims they are .

I've seen some real fast ones with a standard flat top piston and some with pop ups so there you go .