Some thoughts:
Generally speaking, the stock Tucker cooling system works well and cools the engine without issue, even when the engine has to work hard. Is the electric fan in addition to, or in place of, the stock mechanical fan? If you are using a mechanical fan, is the blade the original one?
The 210º temperature really isn't that high.
What concentration of anti-freeze to water are you using. While anti-freeze increases the boiling temperature of the coolant, it isn't as efficient as straight water in giving up heat. A 50-50 mix is generally considered to be the right mixture as long as that meets your freeze protection needs.
Depending on the thoroughness and detail of the rebuild, it's not unusual for a rebuilt engine which has tight clearances to run somewhat hotter initially until the engine has been broken in.
Measure the radiator inlet temperature (top hose) and the radiator outlet temperature (lower hose) and compare the numbers. That difference tells you how effective the radiator's cooling is. I think you should see at least a 20º drop.
I bought one of the laser heat guns mentioned above and found its readings to be of questionable accuracy. Moving the laser spot only 1/4" could give a reading many degrees different... to the point it wasn't believable. I then purchased a digital thermocouple thermometer (
https://www.amazon.com/gp/product/B018QHQSB8/ref=ppx_yo_dt_b_asin_title_o04__o00_s00?ie=UTF8&psc=1)
I found it much more accurate, and with two leads I could compare the radiator inlet and outlet temperatures simultaneously.
Very nice looking Tucker! The mirrors are interesting. Can you tell me what they are/where they came from?