NEW BRAKES....DOT 5?

I own a restoration shop in the Midwest. I have converted dozens of my clients cars to DOT5 with NO issues. DOT3 is Hygroscopic & pulls moisture from the air. DOT5 repels moisture being silicone based. When DOT3 reaches it's saturation point the water settles out, mostly in the wheel cylinders with water being heavier.
If you have ever opened up a DOT3 seized wheel cylinder or caliper you will see the rust mostly at the lowest point. DOT5 doesn't have that problem...
I worked on a 64 Impala that was converted to DOT5, then shortly after was put in storage for 15 years before it came to my shop. The ONLY system I didn't have to rebuild were the brakes! Wheel cylinders, free, NO leaks & master cylinder was crystal clean! Like you filled it yesterday. I was already doing the 3 to 5 switch but THAT made me a true believer. I also worked on a concourse, trailered to car shows, 1955 T-Bird. The brake system was nothing but muck & rust & had been completely rebuilt about 10 years prior.
The reason DOT5 is NOT used in late model cars is that Silicone based fluids cannot tolerate the rapid pumping associated with ABS braking system.
DOT5 will "foam" when the pressure is cycled rapidly, DOT3 (or DOT4) does not.