I’m new to SetCPU on Moto Droid and need help

I'm running rooted stock Android 2.2 on a Motorola Droid. I was hoping other users of the app could give me some advice. First question: whats the best underclock setting for a good balance between performance and longer battery life? How much longer battery life is it giving you on average? Second question: I told it to autodetect the phone and I can seem to only overclock to 800mhz. How do I overclock to 1ghz. How high can I/should I overclock? I'm only overclocking when I play psx4droid. Third question: any recommended profiles to setup? Thanks!