Hi!
I made them specially for my Marutaka DC-3.
Any paint would work, but I use them as they are, just sanded and balanced.Trowing a prop!? Never happend to me!
I run 5% nitro and 15% Motul micro All synthetic oil. 30 years ago I used 20% Castor oil, never experienced any engine trowning props then and not now. When I occationaly run my engines too lean, which dosn't happen too often, they sag...never detonate.