45 lbs at road speed is still way safe.
I used to have a stock 19 inch radiator with no shroud and a 18 inch steel factory fan about 2 inches from the radiator (Due to a spacer)
My car has 65 lbs of oil at 2800 warmed up to 190 degrees, and 45 at idle.
It ran just about what yours does in traffic or parking lots around town, and would perculate (start gurgling from boiling) but not overflow really at all.
I was not happy with that since I live in Arizona, and wanted to drive through hell itself if I wanted to because hell is about 90 miles south of me (Phoenix) and I somtimes need to go there for parts and such.
I probably didn't need to, but I replaced the water pump with an 8 impeller pump instead of the 7 impeller.
Bought a 2 row 26 inch radiator from Checker Auto($180) a 17 inch Jegs electric 2400 CFM S-blade fan($45), and an adjustable thermostatic controller for the fan so I could set when the fan came on and went off (another $35).
I have a 190 thermostat in it and now have a hard time keeping it up to 190 on the hiway because of the extra cooling surface of the 26 radiator.
I drove it to Phoenix last week and it was about 75 where I live and 90 in Phoenix when I left at 5 in the morning.
I got all the way down to Phoenix before the engine got over 180 with a 190 thermostat.???
While I was there I needed to drive around to different places stop and go stuff in town and when it got to 210 degrees my fan came on and brought it back down to 190 and shut off again.
Going back home it was about 105 outside and the engine stayed at 190 on the freeway till I was almost home and started going under 190 again. (180-185) and it was 80 here by then.
Before I did this to the cooling system I flushed the engine block really well with a garden hose and compressor, to blast the water through the block with air. (a trick I learned a long time ago) and a lot of orange rusty crap came out.
I ran the garden hose into the thermostat opening in the intake, with an air nossle from the compressor, wrapped a wet rag around the both of them for a good seal.
Run the water full blast and about every 5 seconds I hit it with a blast of air.
Works really well, as these old engine blocks collect a lot of sediment at the bottom of the cylinder walls after all those years that causes "hot spots" on the inside of the cylinders.
To answer your original question though, sure more cooling surface and therefor more coolant will lower your overall temps as long as you have some decent airflow, and 200 for a few more inches of surface is worth it to you.
Like some of us said though, 210 aint bad so you might want to flush the block real well and see if that does it for you before spending the money on stuff you may not even need.