I followed the advice of the forum and upgraded my gear to edit h264 in cs5, Wow it flys. Now I need to get my scratch disks set up properly and file habits set properly or I will have a mess after editing two projects.

I have a 320GB scratch disk and a 1TB data disk along with my OS Drive.
In Premier when I go to set up scratch, there are 4 options....video & Audio Preview and Video & audio capture.
I am assuming Preview goes to scratch disks and capture goes to data drive. I am sorry for sounding so lame but when I put film files in a project they are already on my data harddrive, are these the files they refer to as capture? My plan is to always have the original h264 files on my data drive in the folder for a given project.....Does that mean I point to that drive when I am setting up scratch disks. I am embarrassed that this is so confusing to me but just learning.....

If I have preview files on my scratch disks, when do I clear them off? After a project is completed and stored?
Thanks