water temp warning, and best gauge color?

[aeronaut]

What water temperature do you folks set as warning? (Assume an accurate gauge and in-block sensor)

And, while my current gauge seems accurate and has some nice options, it's just too difficult to read in daylight when wearing sunglasses.
What gauge, or gauge color, is easiest to read in various environments? White background, black background, digital readout?

[poweredbyg60]

i have a vdo set, black, with white letters orange needle. easy to see in a glance and when reaching for shifter, needles at 12oclock or less things are ok. what degree is not important long as its less then 12 o'clock.
is your warning audible it would have to be loud as heck.