> At about 1.1 - 1.5 fm it “snaps”. The energy in the tension is enough to create another pair of gluons. To put it in perspective, the width of a proton is 0.85 fm. It’s all waves down there so my layman view is probably oversimplified.

That sort of makes intuitive sense, right? If the force were weaker so that it "snapped" at 10 femtometers, you'd expect protons themselves to be somewhere in that size range as well.

(Or am I totally wrong?)

The actual size is not defined by this "snapping" point, but by the equilibrium between the kinetic energy from the Heisenberg uncertainty of the quarks pushing outwards and the strong force pulling inwards. It's actually the same concept as for the size of an atom, where the kinetic energy of the electron and the electromagnetic force define what you would call "size."