Ameyam, go out to where you will fly and look for birds. Not the ones close in, but those a long ways out. What you will probably find is that the first birds you will see at a long distance either on a cloudy day or a sunny day with the sun at your back, will be a white one. The next to be seen are the black or near black ones. The gray and tan birds don't stand out so well. The main reason you see the white and black birds first is their contrast to to the background sky.

So keeping this in mind, the best bottom color is two of highly contrasting colors. IE black and white. Red and white. Blue and white. Don's rule for covering is that the bottom of the wings and the horizontal has to have contrasting stripes that run fore to aft, and a minimum of 4" wide. The top of the wings needs a contrasting pattern that basically runs parallel with the LE of of the wing. Color isn't as important at long distance as the contrast is visible. The pattern change tells you if you are looking at the bottom or top of the plane.

Another contrast tip is to make the vertical a strong contrast to the nose of the plane so you can quickly determine the direction the plane is going, either upright or inverted.

Last, on a very overcast, dark cloudy day, none of this matters much unless you fly very close in. Every thing becomes a silhouette in those conditions.

The challenge for you is to make it look great close up and to make it visible far out.

As to how to apply the decals, the adhesive backed ones need to be very well aligned before the first part touches the covering You may try folding them over the edge of a stiff, thin plastic, like a credit card and once you are satisfied whit the orientation, stick down the center and burnish out to one edge with the card, keeping the other side from sticking down. Then go back and do the same for the loose side. The biggest problem is air bubbles and there isn't much you can do to remove them Getting the decal down flat with the minimum of bubbles and no folds is the best you can hope for. Ido not know how the soapy water method will work with the adhesive backed decals.

Don