I'm going to be replacing mine also and stalling my new red snappers....Personally, I would just make new ones...lots of work but I think less in the end as opposed to trying to reshape the other ones....Do you happen to know the hem one has to make to fit the snappers?
So I went in search of my answer to my question and found loads of info on this lady's youtube channel
http://www.youtube.com/user/renaequilts/videos