photo resolution plus CYMK or RGB

[dehavenphoto]

So far, I am printing all of my small quantity materials on the Xerox Phaser 8400 DP. My photos are srgb and I send the InDesign files to the Phaser as RGB instead of CYMK. CYMK prints SRGB photos really crappy.

Am I doing this right or should I change my photos to CYMK and print evrything CYMK? Or does it really matter? I just want to get the best quality.

Also, how do I judge what size to make my photos as far as size and resolution? For example, if I want my photo to print out in InDesign as 2"x2", should I make it 2"x2" in Photoshop? And at what resolution? I am trying to print the highest quality I can. Xerox states the 8400 prints at 2400 Finepoint (TM), 600 dpi. Finepoint is apparently some Xerox thing that makes it print at 2400 dpi????? So then, do I make my photos 2x2 @ 2400 dpi?

Any help appreciated. Thanks,
Jack DeHaven