I’ve already pointed out the necessity for self-defense-oriented shooters to train at what they’re bad at, whether that’s off-hand shooting or shooting without your prescription glasses (wearing safety glasses, USMC be damned). Learning how to draw your gun with your support hand certainly fits that remit.
In terms of getting your gat into play with a right hand, limb or shoulder sliced to ribbons or shot to bits, the SIG SAUER guy’s got it going on. He’s also a lot slimmer than a lot of us.
For OFWGs, the knee pinch technique is the better of these two suggestions. Which is like saying walking on water is easier than making the blind see. Not to mention that both techniques present a convincing argument against using a retention holster for concealed carry, FWIW.