Howdy D10 ~
Sorry, didn't even notice any responses in this thread after mine!
480P is better from a technical standpoint (for more than one reason), however, 480i might look better to you (though some of the other Prog Scan perks are lost). Simple thing to test if you have both cables, try both configs.
As far as tweaking the output, that's going to vary from display-to-display. On our Sony LCD projector, I like to use the pre-configured "Cinema" mode - it has the perfect settings for most games, though I've found on some action/survival type games, the dark levels still need a little brightness tweak.
Our Wii should be here tomorrow (and the component cable) - so I'm going to go through the same exercise myself! (I'm sure the wifey will say "stop playing with cables, I want to play Paper Mario" hahaha!)