however - i personally cant say a lighter pick helps. from my experience i can say that the thicker the pick, the easier it slides over the strings. i use jim dunlop "big stubby" (3mm). Yngwie himself uses very stiff picks aswell.

I played with Mediums and Heavies my whole life... Try this.... Use a Thin but hold it real close to the tip and make sure the pick is parallel to the strings when you are doing a fast riff.

I know these are minor things but let me know what you think. It seems to make shreading amazing clearer.