I'm just wondering what people think is the best setup for a 9'1" Fireball.
It came with a Rator 8.5" fin (which looks alot like a Wayne Rich Classic), and sidebiters.
All opinions welcome.

I'm still experimenting with mine after years. At the moment I use a 10" single MD3, which is the same template shape as the greenough 4a but just thicker and stiffer so it flexes less and is a bit more direct. I have a 6" WR power fin on the way (for another board) which I'm going to try with a pair of big side bites just for the hell of it. I have tried a number of 2+1 combos and havent liked any of them so far.

I think it depends on what you are trying to achieve and what you like and dislike about your current setup.

I like it best with the fin that came with mine
There's lot's of flex in it and it really draws out turns, I put mine at the front of the box and left in the sidebites, tried it as a single fin but didn't fancy it

I have a 7.5" cutaway w/ sidebites on my spider and it goes like a rocket

Wouldn't suit the fireball though, it's too bulky or somehting, more glide orientated

I would have thought an 8.5 inch fin would be too big to use with sidebites, especially as the fireball has a pulled in tail?

Anyway my 9'3'' is basically a copy of a fireball.
I go between 2 set ups:
A 7 inch cutaway with side bites and a 9 inch single fin.

Single fin is definitely better for small weak waves imo, feels way looser and faster and allows for tighter radius pivoty turns.
This set up gets a bit slidy when theres a bit of push in the waves, I feel I have to be a bit delicate with the pressure I apply on the back foot.

I find the 3 fin set up too stiff and draggy for small waves but definitely prefer it in bigger stuff. Take offs feel a lot more solid and turns are a lot drivier. I feel I can really crank down on the back foot without loosing control. It's also way easier to land floaters etc with the 3 fins.

Couldn't really comment on how either set up affects noseriding and cross stepping as I have a lot of improving to do in that department.

I have a 7.5 inch true ames L-flex on the way which I intend to use with side bites.

I'm looking to use the fireball as an all rounder for the all the spots around where I live (near Dingle), so it could be anything from 1' gowlane to 4-6' point or reef breaks. My last two boards were shaped by keith beddoe who does has the bear licence at the moment. They are both performance orientaed with loads of v through the back of the boards. One has a fin box and side biters, and the other has standard FCS thruster setup which I run with a 3d red tip and goes like the clappers. So the fireball I think is going to be a completely different ball game.
Would it be fair to say that it will probably go best is small stuff with a big single fin, and for bigger stuff a smaller centre fin with a bit more flex and side biters??

I have ridden a fireball as a single at the majority of those breaks. If it is a good size and lined up the single moves towards the back of the fin box (more drive, more hold, longer more drawn out turns), and if it is smaller or there is more scope for sharper turns then the fin moves forward.

The singles I use have a big base for a lot of drive, and narrow tips for good release during turns. I now go for minimal flex as my fins were overflexing and fracturing. I was also finding a delayed reaction during turns and prefer the more direct feel of a stiffer fin.

I am biased towards the single fin approach, as I find the angle of side bites slows the board down, but there are plenty of people using that combo to good effect.

I have a few fins that your welcome to try out.

I thought so aswell but when I tried it out it went really well, it doesn't feel stiff at-all, that fin is really flexible so that makes a big difference

I tried it as a single fin on a small day and really enjoyed, you could walk all over it But went out on a 4ft day with the same set-up it didn't tickle my fancy , I like the feeling of control from having the sidebiter's in, I whack the fin right forward in the box too, the odd noseride is still possible just good timing is essential

If you put the centre fin right to the front of the box with the side bites in, does that not mean that the front of the centre fin is ahead of the back of the side fins?
If ya know what I mean!?!
I thought that the front of the centre fin should be set back a bit from the back of the side bites?

The Fin-box is set back pretty far back on my board so the front of the fin is about half an inch from the backs of the sidebites.

I couldn't do that on my Spider 9'0" because of what you said, I have to keep the fin in the middle, which aint easy because it's really loose

Ah I see