Speaking honestly, although when I'm selling I'm happy to work with buyers to make them comfortable the fact is, the way you suggest sounds like a lot of hassle. If one person is willing to buy a watch cash (or similar) and another wants a convoluted round trip to a watch maker where it may well sit in their safe for 2 months before they get around to servicing it, before I get paid, then I know who I'm going to sell to. I always give first dibs to the person who contacts me first, but if there payment request is out of the ordinary and I will be without both the watch and payment for several months, I'm likely to inform them that we need a different method or I'm selling to another party. Now in your case, buyers may be more willing to accept non standard terms as your watch is more individual and a couple of buyers are likely to be willing to go the extra mile to get it. However, as a buyer it would also put me off. If I'm buying, I have cash waiting and I want my bloody watch! I don't really fancy having to set aside the cash then wait 3 months before I can see my new toy, so you may lose several buyers, which would in turn decrease the competition and possibly the final price.