Yellow won't look good over the black. As with painting, you always should put darker colors over lighter colors. It will be much better to apply your yellow first, then piece the black sections in with about a 1/4 inch overlap. Don't ever put a strip of white to try and make a light color stand out. You'll be adding weight, doubling the air bubbles you create, making a thicker seam for grime and oil to get trapped into, and if you don't match up your edges perfectly it will look bad.
For good orientation, you might consider going the other route with your trim scheme. Since the sunlight is hitting the top, it's going to look lighter in flight. If your top is black and bottom is yellow, that will actually reduce your contrast considerably. The whole point of making the top and bottom different is to improve visibility, so making the top mostly yellow and the bottom mostly black makes more sense.

As for what to use, Ultracote is my film covering of choice. Monokote is fine too but it works at altogether hotter temperatures and doesn't shrink quite as much. You'll need a covering iron and heat gun to apply it properly. A tip on setting the iron heat right that I only recently learned is to put a small square of covering on the iron and find the setting where the adhesive only gets tacky but the covering doesn't shrink at all. That's your application setting. Then find the setting where the covering only barely starts to shrink. That's your low shrink setting. Then find the setting where the covering won't shrink anymore. That's your high shink setting. Do all of your application at the application setting, pulling the covering as tight as you can and as wrinkle free as you can. I like using the heat gun to do compound curves and for shrinking the covering over open structure such as wing bays, but that should be the only place. There will still be some wrinkles that you can't pull out, so don't worry much if a few small ones remain. Then once all of your covering on a piece is done (whole wing done, whole fuselage done) go back over it at the low shrink setting to pull it uniformly tight and get out the wrinkles. If you've done it right, this will fix 80% of the sags and wrinkles. For whatever is left, make tiny changes to your iron setting and get them out. The whole idea here is to use the lowest heat you can possibly use to get a good finish. That way you'll still have some shrink left when the covering wrinkles and sags in the sun and as it ages, which it always will. The number 1 covering mistake is to get in a hurry and go nuts with the heat gun or use the iron too hot and use up all the shrink instead of pulling the covering tight to begin with. The plane will look good when you're done, but 6 months later it will be a wrinkly mess that you can't fix.