What kind of surroundings would help you focus? If it's lushly rain forested mountains, then seems like Saba would be a good choice. It's a lot smaller than Dominica (judging from Google Maps), so I'd think there'd be less temptation to go exploring & eat into your time.
Have you thought about St. Croix? It's got boat diving and some shore diving. From what I read not as hustle & bustle as St. Thomas. I did a couple of dives there on a cruise ship stop & liked that 'sampler.' Researching it, it doesn't sound like it's jam packed with riveting topside activities, but it's pretty, and should have what you need. I assume they drive on the wrong side of the road, if that's an issue. Cane Bay Dive Shop has cottages to rent, if memory serves. I don't know about internet service in the region. Note that
N2theBlueStCroix contributes useful posts about St. Croix on this forum, and I tend to be favorably inclined toward people who do well enough to show their face in public where customers could challenge them, so you might
see what his operation offers.
DenbyS posted
February Dives in St. Croix.
My
Quick St. Croix Trip Report includes input by others that may help.
I think of it this way. Figure you want 2 dives in the morning to clear your head & get in a good mood, but otherwise to work. So you don't need a lot of topside attractions, or a once-in-a-life-time place where you're driven to dive every time you can. Why not go somewhere to enjoy the diving, but be content with that? If I were in your shoes, I be thinking if I went to:
1.) Dominica - I'd want to explore the rainforest.
2.) Little Cayman or Cayman Brac - I'd want to do all the dives I could. Bloody Bay Wall as much as possible. 3 dives/day, oh, yes!
I'd be weighing St. Croix against Saba. Hope you'll let us know which one you did & how it went.
Richard.