I don't put my left hand at the balance point... I'm actually out farther which allows a heavier body to "self damp" and not wander around as much as a lighter, grip less body.
Shot my 500mm on an ungripped 5Dc for an entire week a couple years ago. Never Again.
ETA: I've found that supporting a large prime at the balance point is, in fact, the absolute worst way to shoot. Having your left hand working as an ersatz monopod allows the entire rig to twist in really bad ways. Supporting the lens out at the AF Preset ring (or even out at the barrel/hood joint) gives much more positive control for panning. Just my $0.02. YMMV. Void where prohibited by law.
X 2...
Al
If your hands are the same size as my wifes you'd likely be fine (or outright better off) without the grip. 

