The best thing to do to wood strains after cleaning is to soak them in linseed oil. When the insulators were manufactured, that is what OB treated the hickory sticks with. The insulators also need to be proof tested to working load before they are used. What type of paint are you using on the wood portion of the insulator? I can provide you with the paint number from PPG that IMPulse uses for our Trans*Lite insulators. It has been tested for both UV and tracking resistance.
According to PPG the paint # you gave me, the one that IMPulse uses, is great for fiberglass but not recomended for wood. I used Sears house paint. As for the linseed oil, I tried that- too high electrical leakage when tested. It was better with just paint and you have to clean off the oil from the metal ends before dipping in galva-bright.