There's chain and there's chain. Real Navy chain has flat lozenge shaped links- straight sides, half round at each end, flat no twist, and has a bar across the middle to keep it from balling up in the chain locker.
There's not a lot of readily available info about what the size should be, but bigger ships have bigger chains, of course.
That is simply not available in the jewelry realm, period.
I always leave what came with the kit.
3D has produced some wonderful chain, but so far it's best in the larger scales.