Nick
You are correct in saying that if you are further than 12 miles offshore you can't bust FAR's but FAR 91.101 is just stating where the geographical limits are. So if you are operating further than 12 miles then you need to find alternative regulations. In this case it would have to be under 135 or 121???
Plus if you are going 50 miles offshore and dropping passengers shouldn't the operation be 135!!
In 135 it clearly states what the operating limits for Night VFR are as stated in my earlier post.