The balz pro works well, both 909 and 969 depending on how fast a wing u need
the razor use another fuse but is very popular for that purpose

909 and consider whether you want to try one of the flat tails if you aren't already.

I have used the Medusa Pro 869 for the last 2 years as a one foil quiver.
However, recently I have been using the Balz 808. The 808 has slightly less low end lift but has a higher top end speed and is less nervous when you are maxing it.
The Sabfoil website has a compare feature where you can compare different foils - unfortunately the 940 is not longer listed but you can compare the current range.

Roy said..
I have used the Medusa Pro 869 for the last 2 years as a one foil quiver.
However, recently I have been using the Balz 808. The 808 has slightly less low end lift but has a higher top end speed and is less nervous when you are maxing it.
The Sabfoil website has a compare feature where you can compare different foils - unfortunately the 940 is not longer listed but you can compare the current range.

What size sails are you using with the 808 and what wind strength?