If you use a digital micrometer head you can always work to a specific "0"
I have a guage block that I use to set the micrometer head to "0", which also coincides with "0" on the thimble, screw the micrometer head to the headspace reading I have recorded in my book and zero the digital readout.
I find this way is just quicker and easier for me, plus I picked up a few digital Mitutoyo mic heads for pretty good money when things were a lot cheaper on ebay
I have a guage block that I use to set the micrometer head to "0", which also coincides with "0" on the thimble, screw the micrometer head to the headspace reading I have recorded in my book and zero the digital readout.
I find this way is just quicker and easier for me, plus I picked up a few digital Mitutoyo mic heads for pretty good money when things were a lot cheaper on ebay