I have been using -12 for years with my alcohol motor with no issues.
Have this new Turbo motor on gasoline for the street/strip and drove it for the first time yesterday with no hood and it got to 200 degrees during slow speeds pretty quick with no boost yet

Seems to heat up at idle faster than it should.

Now I am still fooling with timing and fuel mixture but I dont think I am that far off.

What do you guys think? Using a meizier electric pump

I'd use dual #16 lines with a setup like this.

If you're using an engine mounted electric water pump then I might recommend something like this setup with dual #16 return lines.