G'day

From my experience of Sig kits, the differential aileron function (if needed) is built into the torque tubes that operate the ailerons from the servo pushrod. So you should just use a straight aileron arm and the geometry of the provided torque rods should give the amount of differential needed (if it is needed at all). It is a while since I built my Mk 2 and as a result, I don't remember whether the supplied torque rods were offset or not.

I will have a look tomorrow and let you know but basically if you follow Sig's instructions, you won't go far wrong.

Cheers

Mike in Oz