A thermostat will only let the engine cool to 160 then close till it's gets up to 160 again, it will not cool your engine down, unless you live where it's cold out. then it will only let it cool down to the temp, If the motor is going to run hot, it's going to run hot. a thermostat only warms your motor up till it reach's that temp, then opens all the way. It still will go as hot as it wants because of other problems. Unless you have a bad thermostat, then it stays closed and over heats. and yes you need to run a 195 in that motor.
In reality if you remove your theromstat you can run your water pump backwards ( with the right fan) and reverse cool your motor, but then you cool the bottoms of you cyl's 1st, instead of the tops, not as good on the motor.

Unless you drive your motor real hot for awhile, it's not going to hurt the tranny, they run hotter than the motor normally, and usaully warmed up before the motor is.

I think spraying water on your radiator to cool it down will only make a mess, you need to find the problem. If it cools when you drive highway, and heat up at stops, then it's a air flow problem, if it heats up driving & stop it a water flow problem.

Most motors of the 60's & 70's burn oil because the cyl's were worn from lack of oil, carbs are like toilets, they just flush the gas in whether it could use it or not, and washed the cyl's clean of oil and caused them to wear faster. TB & TPI took care of that and the motors last longer. I think Dino oil "was" a good lube, but you need to change more often to keep it clean cause it did beark down quicker. They just took all the zink out and thats what made oil a slippery lube, new oil doesn't lube like it use to, thats why lifters are roller. the only real wear spots are the piston's & lifter bores. Rods & mains float on a thickness of oil pressure, not direct rubbing.

As for your AC, anyone can get anything working, it's how much do you want to pay?

Pat