Hmm, now I'm confused.

Current plan (too late to change now, too far down the wing covering road) is to cover the wing, excluding the wing tips.

Then decide what colour to do the wing tips (leaning towards red at the moment), and cover them.

Then glue the wing tips on to the wing.

If I do go for red, then I will get a join line, but it will be fine. If I go for another colour, the join line wont be so easy to see as the colour will change at that point. I'll try to take photos tonight when the wing is done.

Looking at your photo, you have covered the wing in white, folding/stretching/shrinking the covering over the edge. Then covered the end with the purple, and trimmed around the edge to line up with the wing tip? Just think my method is a little bit neater.

Mind you, if the best we can argue about is how to cover the wing tips, says a lot for how good the plane is.