Tom, As far as the canopy paint, I would just paint it on the inside with lexan paint for car bodies. Painting it on the inside you shouldn't have to worry about it being fuel proof and won't really need to seal it. Clean it real good with some soapy water, dry it well, and paint away. You could even use some Scotchbrite to scuff it a little. I've used a airbrush and also a paint brush to paint mine and gotten about the same results.
For high rates, low rates, the end of the servo horn is good. Well, depending on how long the servo horn is anyway. You just don't want to put it on the end of the horn on the control surface. Stay more towards the middle or inside of the control surface horn. Not sure about 70% for low rate. Just set up the low rates so that it's about what the manual would recommend for low rates and go from there.