Place them on the main where otherwise the spreadder tips may poke a hole in the main. Possibly only happens if you jibe and forget to uncleat the positive mast rotation.
Ken
but the blade has a rotation limiter. I have a hard time thinking the spreaders tips will ever touch the main. Who knows.. I wrote to them about it.
I did put some rotation inducers on the HT for the RTI but the blades mast rotates pretty well so I am not too concerned.