Thanks for all your answers.
Of course ive to work my technik but who doesnt if not a payed fulltime waterman.
My Boards mostly had all FCS II. Only the very first F2 (US, FCS) and scnd Coreban Vibe (Futures) had other boxes.
The following boards where all Gong from france.
There was 2x the MOB 7'6'' one 105L one 120L which only worked as quad because the wide tail as tardy said. The 120L had the thruster option the 105 was 1 Generation later and the Centerbox was gone. Ive used FCS II MickFanning Fronts L and Carver Glas Flex Rears(flat). I had drive and loseness and did not felt anything bad about the fins. That's why i kept the fins because i thought it would work best for me and it would always stay that way.
Next one was a Zero 9'0''. US Center Box FCS II Side Box. Ive never tested the orig. Gong 9isch Center Fin. Ive mounted a Harley Ingleby 5.5''
and some sidefins. Ive played with Center Fin Position, worked best in the front third of the box. I had enough drive to go through lulls could go radical and fast in control, was able to slash a backside topturn and that all with a longboard. Really a great board, stable easy going and surfing limited only by its pilot. I miss this board and would direct take the same fins because it felt just right for me.
Then I wanted something light and compact with no swingweight for the "good" days when no chop and minimal wind so I got my hands on a Fatal 7'4'' 108L. Immediatly the bad awakening, I had to start in deeper section and lulls are not easy to go through because I had much less glide now. When you read marketing of fin manufacture you get the idea twins could be the answer because of sooo much drive. Tested once AM Twin with trailer, felt wrong. MF Thruster Setup mounted, was the best choice. Board is in Sweden now. Miss it a little but, because I had alot fun on Vacation at beachbreaks in france. Surfing atlantic ground swell instead of baltic wind swell makes of course the biggest difference, thats why most watersports adicted people have a board quiver and not one board for all.
Now I have a Karmen 8'4'' one board quiver (lol) classic outline much more rocker, much thinner tail, 5 fin option. Because I've done well with the MF's up to this point, I tested them on vacation in France. We had good waves and you immediately noticed that something was different here. I couldn't tell directly if it was the rocker, outline, thin tail or fins. But I could only change the fins so I tried. MF Front - Performer Rear, MF - Carver Rears 50/50, MF - Carver Sides (flat), MF Thruster, Performer Quad, Performer Thruster. By my standards the waves were very good and had power (10 -15sec).
On vacation I noticed that the Quad was slower and very raily. Back home in the onshore slob you feel it 5 times more because you are riding in the lower limit range. Anyway, I've tested the Karmen so far with:
Quad - sticky, raily, like having a huge bush of grass draging under water on the leash.
Thruster - similar to Quad but noticeably better in all aspects, very controlled, maybe best option for punchy fast atlantic waves
Twin - completely different board, fast, free, easy to edge over, handbrake released
Twin + Trailer - Like twin but less variable, probably better for more control
Keel retro(no Name China) - still on the way to me, hope for more drive but more control than twin, still variable as no trailer needed.
I cant test Single Fin and 2+1. Reverse quad (u mentioned fronts and rears changed (or turn the tip foreward

))should also not work in my case, because I think the rear sides in general are the brakes (perhaps to much toe and/or cant). How do u get extra cant? Do u customise your fins? Making fins shorter is easy as breathing but adding cant should take some more brain and tools. Unfortunately FCS doesn't give very precise specs of their fins, so how do you know such precise data? Any Suggestions for flexi Twins?
Now I've talked a lot about the boards, even though I wanted to avoid it. So let me remind again, I want to know more about what you can get out of fins instead of talking about weaknesses of boards or their alternatives, because there is a excellent thread about small wave SUP's already here in the forum.
So good so far, best regards!