1) None at all.
2) A deep penetrating, hard drying/curing oil. It won't crack but yet will still protect the wood. There's got to be harder drying oils than boiled linseed oil, walnut and pure tung but that's the type of thing I'm talking about.
3) Catalyzed Lacquer (Post Catalyzed) - Hard stuff. Nasty nasty and difficult to work with. Will probably last the longest of the film building finishes.
4) Pre-catalyzed Lacquer (Melamine Lacquer as it's sometimes labeled) is easier to work with and close to as hard as the Catalyzed Lacquer. It has a shelf-life of about 6 months so get it fresh.
Everything else is just going to crack too easily.
I'm assuming this is for actual use and not just display.