Could I recommend that you go to either of these forums?? They have a great beginners (and others) section and are well qualified to discuss the kinds of questions you have. I have read about (and have now forgot) several rules of thumbs, things like watts per pound needed for various kinds of flight. These forums should provide those kinds of things you need.

http://www.rcuniverse.com/forumdispl...?s=&forumid=93

http://www.rcgroups.com/forums/index.php?topic=air-elec