What's a good temp. range for water gauge?

[socialDK]

I saw a how to thread and the op used a 100-300 temp gauge but the highest I've seen (doing minimal research) is 100-280. Is 280 enough? At what temp should the X be running normally?

 

[corkey]

the temp should stay under 200 , if it doesn't that can be bad trouble,,
my normal temp is about 5 or 6 under the 195 thermostat,