The D4
The d4. Ooooooo, what is good for?
If you find yourself using a d4, stop messing around with those charms and start tossing some fireballs. Seriously, when did d4 ever win the day?
If it does come down to those sorts of margins though, where everything is literally hanging on a d4 roll, then don't take any chances, find your best chance on DiceFTW.