My first strat had a guy with evasion( bit like GentlemanLoser have), but Mr.Piper made me realize that you will still get hit due to those high pth items. So the only way I can see to evade tanks is to use an assassin crossbow so your dex become 1 or something like that in the math equation.
But what's the use of doing that if you can equip an exbow on a tank and get better results then evasion?
And since str gives way more encumbrance then dex, you get the enemy encumbered.