Talk to the marina beforehand and make sure they won't give you a hassle. They might have an out of the way place or assist with some crane time. Is it an internal halyard? I'd be reluctant to go up in the bosuns chair with only a halyard supporting the mast, especially if it's not an internal halyard. If you can use the main and genoa halyards to separate bow cleats it would be better to have redundancy.