Looking for some advice/experience in regards to selling Lego second hand

I've got two set I'd like to sell. One is very big and although it came in a very large box, the completed model won't fit in the box it came with.

Do second hand sellers want a complete model though? Or do they want to buy a model in pieces again? It's a very awkward model to transport around a house let along in a car.

Should I try to disassemble it into some large components? Or completely into sepearate numbered bags (close to the original order as I can)?

It should be complete but it was missing one or two very small pieces is that an outrage? Even if I flag it? If I photograph it well and point out where I think a piece or two might be missing would that help a seller?

I'm not looking for profit or wanting to get my money back, but I think I should be able to get some money for it given how much it sells for at retail.