People in colder climates often insulate the Heater hoses, just use that pipe foam the splits and tape in on in a few places
Also E-fan instead of mechanical fan works well, or block off air flow thru rad with cardboard, helps engine metal to retain heat without the constant flow of colder air, lets engine bay warm up a bit more

 

oops on edit, proportional would mean higher than 250 F, but maybe so..

 

Yes, 190degF is normal temp, above 1/3 and below 1/2 on a Ford gauge, just above 1/2 when pulling a load is OK, or going up a long grade