Evans waterless coolant is the way to go on a fresh build. Very high boiling point so no need to pressurize the system ( less leaks blown hoses ect ). No rust ever , never needs changed last forever . Much better heat transfer for better cooling ( #7 & 8 on a Buick straight 8 will like that ) . Cost is just a little more if you start with a total dry system . If you convert from regular coolant the cost can get high as you need to purge all water from system. Must make sure no one ever adds water or your in trouble lol . Evans does what they claim. I wish I had known about Evans when I built my Chevelle and Opel . As these cars set for long periods of time I would have saved money in long run ( new radiator for Opel and hose's for Chevelle )
The Rod shop that did my frame and engine highly recommended Evans. They also recommended Dot 5 Brake fluid for new brake system also as they never absorb moisture. . Hope your project is moving along well. Take care