I have not used them, and this is not exactly applicable to the SP, but a lot of guys do use the H2 fin where I normally surf. The word is that the cant of the fin generates a lot of lift in the back of the board, making it a bit looser/faster. Dont know how that would translate in a board like the SP.
... Chances are they will be a smaller wave set but well see.
Those are the reports I've seen on fora regarding the H2 thruster set. The thrust, if you'll pardon the pun, is they don't hold in bigger waves. One of the reasons I waited for the H3 release.
I've tried the H3s, now I don't know if you could say they are a refinement of the H2s or "another attempt at the perfect fin" starting from scratch, so take from this what you will. I have an H3 tri-quad set, as a quad they're fast and drivey but a bit stiff, however that is using the H3 rears which could be swapped out for something a little smaller. As a thruster set I found them quite good.
By changing the rears it's like creating a whole new fin set anyway, match the H2 in front with something like GQ-X rears and it might not be too loose, something like the R2 QR might make it go like a ratty skateboard with super loose trucks. Might be fun!
I usually hang onto fins that don't work in one board in the hope they'll work in another...sometimes though it never happens. I bought a set of Sunny Garcias tried them in a few different boards and never worked for me, gave up and sold them.
Pete, I should have taken your advice on the Indo Fins for only a few £ difference but was a bit worried about getting stung with an £8 customs handling fee + 20% VAT and then ending up an expensive set of fins...