Ron,
i found a firm here in Switzerland which sells nice (57 or 52mm dia. i'm not sure anymore) Temperatur Gauges with white Face and red indicators... its appearance is the closest to the Stock instruments in a Viper... and its in C°.
This one i mount on the Steering wheel column.
I will check what Sizes of Sensor they offer.
Then i will take the one with the smallest diameter and ask the guys at the local machine shop to make an adapter to fit the small Sensor in the bigger Drain Plug hole.
Thats my Plan.
There are still 400 Miles to go until i have to change Oil again... i hope i can do that befor winter.
If possible i will Post some Pictures here when i'm finishd.