Are there any formulas one should follow when cropping & resizing 4 MPEG2?

[808state]

I am wondering if it makes any difference in quality if you use different numbers when cropping and resizing at the same time in VDub. I know that Cinema Craft prefers black boarders in widescreen that are multiples of 16 so precious bitrate doesn’t become dedicated to the fine line between the picture & black bars. Dose it matter how many pixels you chop from the source I normally will take off 8 pixels per side and 6 for the top and bottom to clean up the rough edges from caps (and sometimes DVD ripps). Sometimes I have to increase these numbers to get a clean cut or to remove any black that might be on the edges as well.

I do all my cropping\resizing with *precise bicubic 1.00* during the editing stage.

Any help would be greatly appreciated.

Thanks mucho!