We mostly use DT Swiss Aerolite and Sapim CX-Ray spokes. Both of them are pretty much identical. Aero, strong, durable and very lightweight.
J-bend spokes are widely available at many bicycles stores and distributors. You can also contact FFWD.
The front wheel only has lateral (direction of axle) and radial/frontal (perpendicular to the axle) forces to handle. The rear wheel however also has to deal with the rider's power transfer . This creates higher forces in the trailing spokes, because only the trailing spokes can transfer the power of the rider to the rim. The leading spokes will slacken when there is a momentum .
Let's say a rider is on a hill and pushes the pedal with a force equal to 150kg . When the gearing is on its lowest (for instance 39x27), the momentum in the hub is the highest. The initial load in our spokes is 110/120kgF in the rear and 90/100kgF in the front. The extra load (due to the drive momentum) that the rider puts on these spokes will be: 150*(175/78)*(55/23) = 800kgF . This force has to be spread out over all trailing spokes. Less spokes means there will be higher peak forces in the rear wheel.
24 spokes -> 120+(800/12) = 187kg peak
20 spokes -> 120+(800/10) = 200kg peak
That could be a reason why other manufacturers sometimes use a lower initial load on their spokes when using 18h or 20h. To keep the peak forces under control. This lower initial load, however, will decrease the lateral stiffness of the wheel (in other words: less force is needed to displace the rim sideways -> not a good thing).
So, therefore FFWD decided to put in an extra 20g, but in exchange we can build wheels with a higher durability, stiffness and more responsiveness. For those who feel that they need more rigidity than our standard 20/24h lacing (cyclocross for instance), we propose the ControlTM version with 24/28h lacing. ControlTM is available on most models.
We use brass nipples on all our laced wheels as part of our 'no-headache' approach. It is such a small weight difference (around 28g per set) that we rather lace an easy serviceable wheel. Especially for bicycle wheels it makes more sense to focus on aerodynamics instead of weight.
Front wheel is pre-tensioned with 90/100kgF in each spoke.
Rear wheel is pre-tensioned with 110/120kgF Drive side, 90kgF Non-Drive side.
(F2R wheels are set up with 10kgF less for both the front and rear wheel)