After running a few experiments in an effort to reduce noise created by movement at the aka knuckle (most noticeable in choppier conditions) SLH have created a simply Island Aka knuckle dampening kit, which simply consists of 8 nylon washers. These are used by positioning them between the crossbar and aka knuckle joins and are very effective at reducing excess free-play at the knuckle join, which in turn reduces noise.
Install by removing the protective cap at the ends of the aka, undoing the set screw and removing the shaft that connects the aka to the crossbar insert. Re-assemble with nylon washers placed at top and or bottom (it is recommended to use a bit of Loctite when re-installing the set screw).
*8 washers are included in the kit. Note that you might not be able to fit 2 washers onto each aka. If you can't fit 2 washers, only one will be required. So far we are finding that we're able to fit 2 washers to most forward akas (where there is usually the most free play) and only one to the rear akas, but there will always be exceptions.