Hi colegues:
Sorry by my poor English language.
I measure rounded tables starting with the standard glass gage and one cigarretes papel such come double.
Such papel have very little density or thickness.
Are ideal for mesure where start rounded table. Later i found eight point each one of 0.010 in density in milimeters. For ex.: 0,010;   0,020;   0,030;   0,04;    0,05,   0,06, etc.,  This is adequate for me.
Later - nobody can  negate it- the end calibrate or ending of facing is define later the benchmark test and generally, it is necessary to do corrections by away of the exacts measurements.until take a good end.
Fraternally
Silverio
From Argentine Patagonian