How do I rig a Kino Flo to a gobo arm like this?
The photo shows two grip heads, two arms and a c-stand. The kino would have its normal mounting plate (the one in the second photo).

The two grip arms are interlaced together; this makes them trombone-able (adjustable in length), stronger, and gives the gag a longer reach. One grip head attaches the arms to the c-stand, another attaches the kino to the arms.

I use this rig all the time; it works better if the stand is a junior stand and the grip arms are attached to the junior stand with a junior lolly-pop (much stronger).

Cardellini clamps can indeed clamp a stud to many things, but they aren't the best tool for this rig: you want a 5/8" female receiver for the Kino, not a 5/8" stud.