I'd like to toss out another thought for you, ie my buying decision and rationale.
Although you can't see my bottom in my avatar, it is a deep V and nothing semi about her. She is capable of 27-28 knots (my "fast" cruise speed is 21k), we usually cruise at 8.5 kn. At that speed we get 2.1 kmg, which is double your target, BTW, at 21k I get .77kmg. My boat is powered with twin Cummins 6cta 8.3 litre diesels. Turbo and after_cooled, but mechanical rather than electronic controls for 450hp each.
I'm not going to go into why I prefer deep Vs other than to say, the worse the weather the faster I go and the smoother it is. If you get interested, I will go deeper.
I am not advocating for you to follow my example, other than to say "YOU" control the speed and the economy. I wouldn't, and didn't, get hung up on SD, FD issues as trawlers come in all bottom types. We use our boat like a trawler most of the time (my sailor friends love our gentle motion in a beam sea when we are slow, as long as not slow and large beam sea lol) but the speed is also nice.
The Ft. Lauderdale boat show is soon, if any way possible, you really should go as the selection of boats will amaze you. You might see many other well constructed brands (such as ours) and allow yourself a wider breadth of knowledge and variety.
1 nmpg, is not hard to do with most boats, set your goal higher
Once you decide, you might see us in your cruising grounds going slow.