I found that bright and light on the top of the wing along with something dark on the bottom worked best for my eyes. But on the tops I "mark" the wing tips by including big trim patches of the bottom colour as well. Or if the wing is insomething like red I'll do the tip trim "patches" in yellow or white. The idea being to produce a marked contrast which is easy to see.

The exception to this being if I use a transparent covering. Then it's transparent red all the way with big trim patches of some sort of white on the upper tips. This combo works darn good as the upper side shines out nicely in the sun and the trim patches appear very dark when seen from below.

As for the motor setup you're in luck in a way. The BoT is well known to have a too short nose. This means lots of nose weight. So replace the front end with a good stout motor and even set it up so it's a little more out in front as much as you can manage and not ruin the nose profile. Plan on keeping all the heavier items as far forward as possible as well.

I don't know what the overall weight of these ARF Birds come out at. But a good motor and prop combo would be something that provides around 80 to 100 watts per lb for a strong but not vertical climb and something up around 120 to 150 watts per lb for a truly missle like climb. A 3S or 4S pack would be a good option along with a motor Kv value that works with your chosen pack voltage to max out performance with a 14'ish inch diameter folding prop.