Is there any technique to grid starts? Bogging, not spinning

I’m in a league driving a Porsche GR3 and the starts are where I always get eaten up on the standing starts.

I’ve tried setting TC to 0 to allow for some wheel slip but that doesn’t seem to help. I’m on a wheel so the next thing I’m going to test is using the clutch pedal and holding the ebrake but I’m not sure the clutch pedal will do anything since it’s a sequential trans.

Any idea if the above might help? Or otherwise any suggestions?