Hey Randy,
I don't think there is a standard dimension for freestyle, or even combat nunchucks. Dimensions vary from 7 inches long to 15. Round sticks and octagon. Sqrounds even. Square.
Some freestylers prefer straight nunchucks, others favor tapered. Taper can be mild to extreme.
Foam, PVC, acrylic, rubber, graphite, wood, metal...Light weight and heavy. Freestylers have different opinions.
Length of cord or chain is also a matter of preference. Some Chinese chucks have 10-12 chain links, while Prochux have a 1 inch four cord connection.
Combat nunchucks probably would be best with a chain connection to defend against blades. They may need a farther reach, meaning a longer chain and/ or sticks. The handles probably would be octagon wood ( the edges will injure your opponent more ) or metal. Studded wood sticks may work well also.
Mini chucks, 8 inch handles with a 10 link chain may work well in street fighting situations. Plus, they are easy to conceal and carry, if you dare.