I've taken to replacing the hand spring only because to fit a new hand is a pain. I remove the old spring (or fragment thereof) and replace it with a length of bobby pin. You need to file a little pair of notches in the bottom sides of the new spring so you can stake it in place. You need to slightly flare the crimp into which the spring will rest then pound it down onto the new spring and stake the new one in. Save the old spring for a reference to get the shape and length right. Otherwise save the old hand so you can get the exact length and shape onto the new one so it'll work right.