The thing with both the kitchen thermometer (love the idea!!!) and the oil plug thermometer is that they are next to invisible when riding.
I don't think one can simply stoop over and peek while at speed.
I found an interesting three gauge kit, a mere 1 1/2" dia. each, at... whatever car parts store.
Oil pressure (sensor goes into the iol service port next to the right footpeg)
Oil temperature (sensor goes to the oil service port under the sump, next to the oil drain plug)
Volts (sensor goes to the ... d'uh ... battery !)
Intend to fit mine next autumn when the leaves fall and make a mess of trolley tracks