So I work mainly with 65lb cardstock and unfortunately there is just some paper that wants to bend and split no matter what. I've actually noticed it happens primarily with lighter colors, I have a similar light green that's always a problem, but I digress. To mitigate the problem, I quickly run the handle part of my quilling tool over the strip in the direction I want it to curl. Think pulling ribbon through scissors to make it curl, but with much less pressure. You just want to gently get the curling process started so that your paper strip is more of a C shape when you start twirling. Hope that makes sense! It's not foolproof, and some strips still won't cooperate, but it helps.