Being a mediocre wavesailor and trying to improve while living in a fairly light wind area in Florida, I've had kind of similar thoughts. I don't particularly like trying to foil in lighter winds if the shorebreak is a major factor and would much rather have a fin, similar to you. There are some spots with more bump and jump conditions in light wind, with knee to hip high pretty clean swells that often have enough push to get you on plane on a fin on light wind days.
On the big 11'8" Link I've got, I felt really comfortable holding a 7.5 or more and getting in some light swells, but that thing is massive and heavy and difficult itself to carry to some spots with longer walks from parking. My Dyno 115 is a bit too low volume to feel really comfortable going out further if the wind comes down (I'm 90kg at the moment). The Blast 145 was floaty but in swells and chop it really starts to be uncomfortable if the power comes up because it has a wide nose and not a lot of vee.
My compromise was to go for the biggest Kode, and I've had 4 sessions on it since I got it less than a week ago. So far I've just run it up to a 7.5 even though it'll handle an 8.5. The day before it was really light but I was getting some swell rides and planing a couple of times by pumping up, and yesterday it was underpowered but I got a 2.5 hour session of just riding around cruising up and down swells except when there were lulls.
I don't know if it would be as comfortable holding a 5.5 in similar wind, as even in single fin mode it probably would be lacking power and not having centerboard probably wouldn't get upwind as well? But so far the shorebreak here isn't too bad to get a 7.5, 8.0 or probably even bigger if it is marginal conditions, just depends on tide and how onshore it is.
The conditions haven't been the right direction yet for the bigger wave spot where sometimes it is more onshore and I've had a hard time punching out of the inside with the dyno, but I'm thinking it'll be a huge improvement and will let me actually ride on those days where otherwise I'd be getting beat up on the inside.
Someone I know has a bigger exocet x-wave but he said it doesn't plane up that well (also no centerboard) compared to other designs. I can't remember if he has a bigger longboard that's also exocet, but I think he was having a hard time finding one too.
If they could somehow sneak a centerboard into a board the size of the Kode, as it's almost the same outline as the Dyno 115, it'd be truly magic but I don't think it's possible. But that would enable smaller sails in the light stuff if that was what you are after. Here are examples of what I mean, both with a 7.5, both very recent. Swells are similar but first was marginal with only planing in the bigger gusts. Second is where the average wind speed is planable with a 7.5 and pumping or getting a boost from swell. Not true wave conditions really but it's best I've got at the moment.
Images of it next to the Dyno. I was surprised by how close they are. The kode is only 7cm wider. And I haven't used a thruster setup yet on the Kode so I can't report anything on that. I like them both and they feel very similar to me but that may be more of my skills limiting my ability to perceive the differences. There just aren't a lot of days here where I can really get out and get the Dyno dialed in with my smaller sails.
