@GirlonFire,... Hopefully someone will chime in here who has successfully married an FP with a Halcyon wing.
My FP precedes the Contour model, but I describe in the old thread here (Freedom Plate: First Dive) how I modified my (originally slot-less) Halcyon wing to work with my FP.
One other thing: I will sometimes dive the rig without my FP's wedge thingy. No issues whatsoever--except this requires a bit more fidgeting around when you switch the rig to a fresh cylinder.
rx7diver