In any case, I looked for a teardown online in hopes that it would show the actual spring mechanism for the Z-Hinge...but all of them seemed to have skip that part. So...here's a photo of the ACTUAL MECHANISM responsible for the "snapping/springy" action of the phone. As you can imagine, assuming you can get to this point in terms of disassembly, tightening up the mechanism is SUPER EASY. All you have to do is take out the spring, stretch it, put it back in. I think the only way they could have made this mechanism smaller and more reliable is to have used a tiny hydraulic piston in place of the spring, but since I'm an EE and not a Mech Eng. well, what do I know!
Link with instructions for taking apart your phone. You will need a T5 Screwdriver and a puny Phillips Screwdriver.
Ok, without further ado:
P.S. I can have the KB open, G2 upside down and shake it fairly vigorously before it will begin to close now! Definite improvement!