its probally the video camera but in daylight the darkblue / black shows up pretty good. Check out your local clubs and see if anyone is doing combat over there and see for yourself. Its a sight to see.
For the sticky stuff, no there is no limit. There is no rules, that i know of, that you cant have it. I know kurt let me use some of his tanglefoot and gosh that stuff is sticky and nearly impossible to get off the car seats. heheh.. Covering on these models are usually colored packing tape which makes the wing that much stronger. My ripper has econokote on it, though lighter its not nearly as strong.
Granted i havn't flown combat in a long time as time is becoming more scarce. I do like to take up my plane for the fun of it. It is a very fun plane to fly but could get nerve racking at times, as your always on the sticks.