Small

Woke up early this Sunday and tested telescopic gauge, vernier and dial bore gauge with 28mm ID ground/hardened/industrial needle bearing ring.
Vernier is most familiar to me and I'm getting pretty close to readings that I should be getting anyway, but finnish is good, freshly bored hole not that easy on all sizes.
Telescopic gauge was most random method to me. Firsts of all, it's cheap one and not very smooth to start with. Lot of feel is involved in measuring and often I get close, but there are few times that I'm off way too much for comfort. Should visit someone who has a good set and knows how to use it. My problem seems to be nipping just right before tilting the shaft and holding it right. When I'm measuring it with mike, I'm on more familiar ground.
Now, the new cheap bore gauge: Fiddly to find the right anvil and set, but I'm getting pretty good consistency with it, takes a little wiggling, and to get last division right takes a little time, but I found that it's easier to get pretty close.
However, I'm very aware that because I know the "number" I'm trying to read it. Everyone knows this mind trap.
I'll have to test it with something before real thing. Just to figure out how measurement goes on a bore I'm making on lathe and all those tool post and rough finish to deal with.
I turned one plain back plate register today (4 mm deep, 100mm ID) used vernier. I was aiming a little shy, but in the end I was reading 100,00 mm. But it was hot and my left ear channel was filling up with cast iron dust/swarf. Check that tomorrow. If it comes too big, it will be fine catch plate!
PekkaNF