Pros and Cons of 1 2 or 3 to choose to attach to shackle.

[john_morris_uk]

I think you're over complicating it.
Connect your 3 meters of chain to the 60 meters of rope and only let out the amount you need.
If you can't leave it connected up all the time then use any of the options, oversize it and you'll be fine.
Your boat won't put that much pressure on it.
If it ever did seize you can sort it out when you get home.

Agreed. I didn't appreciate that it's a 19' open day boat...!