This is the same link AA posted in the BBrawl thread, but by your reaction I assume you missed it. Just replace "scrape off point" with Shield damage, and attack power just means the percent an attack deals. G&W's #3 hammer has a shield damage property of 25, and deals 6% fresh. This means it will eat 31 points off of a shield's health. Oil Panic has a Shield damage of 0 (like most attacks), but can do 62% regularly. It completely devastates shields.
Anyway, I'll get to working on the frame data thread. Thanks for your input.