Rory,
 
Bill likes to gamble. Cable ties break down from ultraviolet  exposure and 
will fail after a few months in the sun. Instead of  trying to place small rings 
inside the turnbuckles, use a larger size and go on  the outside. They are 
easier to work with this way. Needless to say, if you go  this route, you will 
want to place some protective PVC tubes over the stays. We  have had recent 
discussions on these, but if you need more information, please  ask.
 
Rummy