A cheapo harbor freight one will work just fine. Get a magnetic base, put it on your flywheel and spin the crank to take measurements. It's all relative so the indicator doesn't have to be centered properly. As long as it's held down sturdy all measurement as relative to the same position and therefore accurate.
1" movement means exactly that, there's 1" of movement on the stem (the part that depresses into the dial gauge)
A .001 readout is perfect for automotive use, indicators in the .0001 and .00005 range are for use in extreme tolerance applications ie: precision grinding etc, etc . You will get crosseyed trying to read it. The bore id of a bellhsg would read like the rocky mountains. A .00005 indicator only has a total dial readout of app .004
I think he is refering to what movement is, not 1" of travel ??
One movement is one needle on the face ,some indicators have more then one needle, on some a small dial that will keep track of every .100 of movement OR a revolution or the larger needle.This helps when you use a 1" indicator or one with longer travel.
Kinda like a wrist watch that has many different dials on the face