....can be found somewhere in subsim. Either this forum or the SH4 Mods forum are a fountain of useful information. You are right the manual sucks, this forum is the place to start. Use the 'search' function with keywords and you'll usually find the appropriate thread with the answer you need.
I'm not sure what you're referring to ref the widescreen stuff. I've got a 22" flatscreen with 1680 x 1050 resolution. I haven't made any tweaks to my video card outside of the game (apart from the resolution) and haven't touched AA at all (it's application controlled). No issues with widescreen at all (I'm using an nVidia 7800 AGP card). Having said that there's lots of 'experts' here who will no doubt point you in the right direction.