I forget where I was posting these before so hopefully here works. I found a longstanding error with the shield DS formula that was de-valuing large and tower sized shields. Unless anyone can confirm a flat -5% and -10% penalty versus melee attacks with those shield sizes I feel confident that should not have been included. The latest update can, as always, be found at:

http://gsguide.wikia.com/wiki/Training_Spreadsheet

Keith/Brinret/Shiun

Be nice to Wyrom or I will cut you!