The inside prob. looks ok cos you can only see it from one angle and the light isnt on it. On a big flat pannel like a door or wing, you will be able to see every move you made with the can.
As you wave the can from side to side (or up and down - whatever) the metallic flakes in the paint land at different angles affecting the way they catch the light.
Normally when spraying a pannel your last "drop" coat is sprayed from further away and all at the same angle to get an even coat.
An aerosol cant do this cos if you got far enough from the pannel to cover it evenly.. the paint will be dry before it gets to the pannel.

You might JUST get away with a straight colour.

Why not hire a compressor and spraygun and do it properly if you're feeling that brave.

(incidentally - I'm not a sprayer.. but have made enough balls ups to know what aint going to work )