Having a great deal of experience building off-road rock crawling Jeeps with big engine/small grill area issues, I’ve spent far too time researching cooling issues. This really helped when dealing with my own, so common Model A cooling issues.
I had always adhered to the 50/50 antifreeze logic. What a great way to sell more antifreeze. My research showed me that in the “rarely freeze” climate in my area of the California Sierras, l settled on water + 15% antifreeze, which offered the protection I needed/wanted. This combination got me to the results I wanted keeping the old girl cool (another unexpected benefit, the reduction of roadside pauses has kept the wife cooler). Lately I’ve added a bottle of Water Wetter. I know it’s not for everyone but it and MMO make me happy.
My last couple of Model A’s with cooling issues were ultimately cured with new radiators. Had I jumped on the problem sooner I’m sure the big radiator expense could have avoided. I’m now such more aggressive with my preventative maintenance.
I apologize for my rambling, so boiled down, I would encourage your research to include information from outside the “Model A” world. Some of our issues are also concerns shared my other Motorsport enthusiasts.