If space is a primary concern the saw in a can is my choice.
The only caveat is to use it a few times before packing in any kit. They are very stiff until use loosens things up.
I bought mine for a whole $1 because it was returned as defective.

I like to pack mine well oiled. Rust isn't a problem, so much as sap which plagues all saws.
Just like the diminutive wire saw, the keyword is slow and steady.it is vastly superior to a wire saw.

Remember, wire saws were a RAF escape kit item for silently cutting through seasoned lumber.