The length of the offset between the two holes on the roadlink are all the extra length you might need in a chain. Not very much is it? So I'd not worry too much about it. Your options to get extra links are many if you think about it carefully. An LBS, another cycling friend or acquaintance, a bike coop, and etc. Will waiting for another to ship hurt your timeline if local sources aren't available. You could just buy two, but I think you'll wind up with a spare chain sitting around for years getting in the way and then being lost by the time you need it. At least that's what happens when I try to plan ahead with long term inventory.