Better to convert your completed PAL project to NTSC. Export as
lossless AVI using Lagarith as the codec, and then use Dan Isaacs'
dv2film AviSynth filter to convert to NTSC.
Tutorials to get you started are here:
The command you'll use in your AviSynth script is dv60i50i("lossless.avi")
Post back if you have questions.
Not sure what all that means, I am still at the beginning stages. I am using Premier pro CS4 and Encore CS4