Agree with Rapt that you're trusting a lot to the whipping cord and its ability to be so constrained that a knot can't get through. The BPL AirCore stuff is pretty thin, even a stevedore knot is not so big.
I wonder aloud and with no experience at whipping ends on DIY hammocks but ignorance never stopped me from mouthing off before whether you could take a page from the Hennessy manual and somehow use the cord that comes through the whipping as a ridgeline to be also the whipping cord, and perhaps even the cord that goes out to the rings. One length of rope to do everything. (In the HH way the suspension cord does the whipping, and the ridgeline is threaded through one of its loops.)
well I'm wasting time writing this, just as you are wasting time reading this.
Grizz out and nose back to grindstone