just noticed on your pics that you anyhow have a line between the block and the rotator arm...

actually that gives you an interesting option:
find out what is the minimum rotation you want to ensure the mast can always rotate (probably when sailtrack pointing to rearbeam etc...). If you now make the line so long that the block touches the opening in the tramp and you have minimum rotation, you can always easily come to this (strong wind)position by just pulling the rotatorline in till the block hits the tramp. and you will never encounter the problem I talked about, that you pull the rotator tight and when someone moves on that tramp it pulls on the rotator arm...

just an idea...