What Image Resolution to Work with in AE ?

If my end result should be DV resolution (720x480) at 30fps what image resolution inside Photoshop should I work with to maintain crystal clear and crisp video.

Here is my workflow :

My projects are 30 secs long and mostly just opening screens, or animated backgrounds. I do all my design in Photoshop and bring my PSD file as a composition into AE.

What resolution should I work with in Photoshop ? Should I use 72dpi 720 x 480 or 150dpi ? Should I use 8bit or 16bit ?

I just want my end result to be clear and crisp and not fuzzy ?


Thank you for your help !!