RE: size of a flexy cable?
I think there are a couple sizes near 1/8th of an inch, and then the 3/16th one for larger engines (then of course the 1/4th for engines that are probably beyond what most folks here use).
What I did, was I picked up a straight edge and a couple drill bits. Put the cable and drill bit flat on a table about 6 inches from each other, then lay the straight edge on them (on the shank of the drill bit, not the cutters). If the straight edge is parallel to the table, then the cable is the size of the drill bit. It works...
As to left or right...most cables are going to be for counterclockwise rotation of the prop. I think the only application that is not is a dual prop setup in which one prop spins the other way. Anyhow...if you lay the cable on the table with the prop end toward you, and look down at the cable...the winding on it should go from bottom right to up and left.
Sean