I'm also like cantSUPenough that I'm average and are always saying I don't recognize a change in fins and setups. But I'm trying to find out because I notice that a quad set-up is faster than a thruster set-up with normal fins. Maybe an interesting topic about fins is the FCS2 and portal sup shaper discussion in this podcast.
I bought now recently the C-drives and the Quabba's have some standard Futures fins and MFC's, So I will test it out and make up my mind about these fin topics myself of course. While reading this interesting thread I'm wondering if my "toe-in" is a bit more than average on my Quatro carve pro, so I'm leaning towards jarvisIan fins that they reduce in my board the "toe-in" drastically. curious about the opinions:

But my Naish has it as well:

The RRD (cosmo pro 8'5) and that I had has much less toe-in (I think it's almost straight compared to the other 2 board above):

also, the Gong Fatal 7'7 120 liters (sold as well) has less toe-in compared to the Quatro and the Naish (yes Colas, I have to admit I purchase the fins based on the color and not on the performance, Kalohe Andino FCS2 fins):

My fastest board that I have owned and rode was my fanatic all wave in a quad set-up, this board still has toe-in and the RRD was definitely not faster in a quad setup, so maybe the volume (Fanatic 9'0 159 liters vs RRD 8'5 130 liters) and length difference is also a factor: