I'm getting totally confused about the best settings to use for tutorial vids I upload to Google and YouTube in H.264 MP4 640 x 480 resolution. Some are good and some "stutter" but I cannot figure out why thay differ despite some upload tests - I feel I'm doing something fundamentally wrong.

I've read elsewhere that YouTube is in the process of converting all material to a higher quality so that may have something to do with it?

I record in PAL (25fps 1.09 aspect ratio etc) for DVD and my personal use because I'm "downunder".
I have and use all the preferred specs for Goog and YT.
I'm using Premiere Pro/Media Encoder for editing/conversions.

Q1. G/YT want square pix and 4 x 3 format - should I crop the screen before I convert or tweak the conversion settings to have the encoder do it?

Q2. G/YT want frame rate of 30fps - do I leave my settings at the PAL 25fps and hope for the best or somehow convert from 25fps to 30fps using say Adobe Soundbooth? or, change the fps during encoding?

Q3. Should I simply record at 30fps/4x3 etc and then convert to PAL and if so can it be done without creating the same problems in reverse?

TIA