Sounds like a good idea. Some have suggested using "Pam" cooking spray. Take it from me, doooon't do that! Bugs do come off easy but what a greasy mess, especially if the stuff heats up in the sun
I've used Rejex with moderate success. Bugs still have to be wiped off but removal is easier.
I have to make a 100 mile trip next week through the thickest of the bugs. Maybe I'll try the RainX.