Gauge plate template:
Taking the base line horizontally through the screw hole centers with vertical (90 degrees) from the needle pivot which is midway between the screw holes, the placement of the temperature markers is as follows:
90 C @ 80 degree angle
100 C @ 90 degree angle
150 F @ 64 degree angle
180 F @ 72 degree angle
210 F @ 93 degree angle
240 F @ 105 degree angle
270 F @ 125 degree angle
Are you able to correct the angles?
The center to center of the screw holes is 0.852" which provides scaling, I think.
This should be the value set needed to diagnose, adapt/adopt another sender or gauge, specify a logic circuit, etc. If one simply wishes to have their gauge display temperature, it's probably far less effort to buy an overlay such as the one offered on the Thermobob web site.