I never understand the difference between New Game setups. So like, I'm starting a New Game as Newcastle manager, and I don't plan on moving clubs (unless maybe, the Big Four

). I'm running the game on a laptop (Intel Pentium 1.6 GHz with 1 GB RAM and Intel 855GM mobo, on Windows XP). I have other things installed on this laptop, so it's imperative that I set-up the new game as light as possible to ensure a smooth playing experience.
My game plan is to take Newcastle to European glory

, achieving it by being clever in the transfer market, and at the same time nurturing youth players for the future. I'll retain the current players/staff for the first half of the season (no transfer on first window for all clubs). I'll be playing casually and mostly breeze through the matches with built-in tactics and training schedules (I'll change things as I go).
Now, here's my questions:
1. With my laptop spec in mind, which active leagues should I selected? Obviously England, but should I set the lowest active leage as EPL or CCL2 (or even Conference)? The argument for EPL only is that I'll only manage EPL clubs, while the argument for CCL2 is that I'd like to loan my youths to the lower clubs.
2. Is it necessary to activate (though viewable-only) other European leagues, in order to simulate better experience in playing UCL or UEFA Cup? Also, for better simulation of the clubs player development? For example, if I don't active the Serie A, would Inter be top of the pack forever and their player don't develop (ie, become unhappy or injured)?
3. What is the difference (to my game) between database sizes? Obviously more players/clubs/staff, but does the amount of quality (regen or real) players and staff differ between small and large? I figure all top players/staff should already be included in small. Also, small database counts a lot to the processing performance, right?
Thank you in advance for your recommendations.