Here is your answer Chris Slicks:
MOCAL inline thermostat -12 AN fitting and 200 degree thermostat.
Remote Oil Thermostat - -12AN High-Temp Mocal Remote Oil Thermostat
Canton racing makes an inline thermostat that opens full at 215 degrees, -12 AN as well.
www.cantonracingproducts.com
Your parting out the same idea as my kit, IMHO 200-215 is right were the oil is at perfect Op. Temps. Both company's got quality parts. I know you said sandwich plate, and these are inline units, I know you can get a special order sandwich plate through MOCAL with a different thermostat other then 180 degrees. I just prefer the inline units and have used them before.