To my way of understanding, the idea behind center-weighting a cork/balsa/styrofoam float is to detect what is known as a lift bite.
So, purchase a Comal, unweighted (or weighted if you need casting distance) styrofoam float. Be it spherical or dually-conical and attach it to your line directly above your FNF jig. Add the smallest weight of split shot (SS) to the mainline immediately atop the bobber in order to cock the bobber at a 45 degree angle in still water. You can further adjust this angle by adding additional weight to either the top or bottom of the float.
Test this angle in still water.
Adjust the weight of the SS until it's ready to fish. The bobber, laying on its side in the absence of wave/wind action, will indicate a lift bite.
As you might discern, I don't use the 3-way rig. However, I am a river fisherman when it comes to FNF. Extremely long casts with weighted floats aren't necessary to me. Nor is the 3-way swivel.