I've been using The Big Wave mod since the beginning. IMO 2x is about as realistic as the game will allow (and even that is pretty wimpy) however using that setting you"ll find that running surfaced your engines will be constantly cutting out-the boat will think its submerged most of the times-very annoying.
Second issue is at 2x and in a bad storm the smaller ships will capsize from flooding. This has been solved to a certain degree but still happens.
I'm using 1.5x for awhile now as it gives a better overall balance.
Try them both and you decide what works best for you.
