A good size to start with is one that calls for a .60 size glow engine. That will get you around 70 inches of wing in a trainer, so as long as you don't let it fly away from you you'll be able to see it fine. I have issues with depth perception due to a lazy eye (never could catch a football) so I understand the concern. Your big struggle will be lining up the plane for landing approaches and judging where on the runway you are. Surprisingly though, normal flying doesn't rely much on depth perception since the distances are so far. I would not color the underside of the two wings differently. Make the top a light color and the bottom a dark color and you'll do fine. Yellow, pink, and white are good top colors, especially if you put a strip of your bottom color across the leading edge to make it easy to pick out against a light sky. Black, dark blue, red, and purple work well for bottom colors. Do a search for classic pattern (SPA planes) trim schemes to get an idea for what shapes in your trim scheme make the planes easy to see.

For plane choices, have a look at the sticky at the top of this forum titled "what's available." To get the plane and everything you'll need to go with it, expect to spend about $600 plus whatever your club dues cost.The park flyer route (like the Apprentice that Hawk131 suggested) will be about half that, but not nearly as big nor as tolerant of the wind.