SouthernAtHeart:
I'm not sure what kind of current/voltage is suppressed when the motor shuts off. The schottky diodes I've seen used 8518, have a 1Amp 40Volt rating...
So I guess these are okay... ?
The diodes take the current the winding was taking, so get ones rated for that current.
The issue with dual diodes like this is whether they are common anode or common cathode - for a full H-bridge you need one dual-anode and one dual-cathode.
If you can find dual diodes that are in line (ie anode-to-cathode on the common pin) then you need 2 of those.
You might as well find a schottky bridge rectifier which has all 4 diodes in the right circuit!