292 options for temp gauge sender

[leegreen]

I'm swapping my '52 from a 70s 250 to a early 60s 292. With the 250 I had electric fan switch in the water outlet at the front of the head and a temperature gauge sender in a NPT threaded boss on side of head near the carb.

My 292 head does not have a boss for temp gauge. I want to keep fan switch in the water outlet and the 2nd threaded boss on the outlet is needed for the thermostat bypass hose.

My choices are
1) the threaded drain plug fitting way back at lower left rear of block.
2) use a thermostat housing I can tap for a fitting (cold side of thermostat)
3) put a hose barb T into the bypass hose (space is tight with PS pump nearby)
4)?

Any suggestions or comments ?