High pip off-school spells are useless, and correct-school attack spells you can't add those sun school boost spells (the giant fist +125). I select the wand I like by appearance, then stitch to it the wand I like for function. It looks really awkward though if you stitch a wand function to a hefty weapon. Waving a giant battle axe around in the air when casting a spell looks weird.
Upon reflection I wish you could use the sun school boost spells to the wand card spells. Then the offensive wand spells would become useful. Perhaps this creates school balancing issues in PvP.
Currently I find only the only useful card-carrying wand spells to be blades, traps, and shields.