I can't give any better than the guys have put out already. I would go with the close sewn hinge or replace some wood and redo the flat hinges. I try not to use less than 3 hinges on a surface for safety reasons.
Dental floss or dacron thread or kevlar tow or thread. You can get free Kevlar tow from anyone who does fiber optic line installation. Fiber optic line is a 3 part line. 1 outer plastic tube, 2 Kevlar tow and 3 a thin glass like element. Be carefull removing the parts, the fiber optic line can stick you good. Don't ask me how I know[:-]
kevlar is real handy in model building get a good supply they will just toss out the short pieces anyhow. Short pieces to a fiber optic splicer can easily be over 10 feet[8D]
Many phone or computer system installers will have this stuff. Kevlar is my favorite composite as it has no splinters or "stick in ya" properties.