I would think his point will be that the ropes of the harness and whichever ones they were pulling would cause the strangulation-like swelling of the face and purple discoloration.
One of the reasons I believe Kat's first rendition (to the defense) rather than her Grand Jury testimony is because of the way she describes Lizzi dying, the only movements she relates that Lizzi made at all in the GJ was the inwards facing of the tops of her feet and her hands/wrists pulling up near her bust - that is simply unbelievable (esp. since Lizzi was sitting up at the time) and tells me she's never seen a person actually be strangled.
At the very least the victim is going to grab at the rope around their neck, do anything to try and get the hands or rope off of them, kick their feet and make more noise than a 'small yelp', but none of a typical struggle is in Kat's second story. Her first story is much more believable, whether Lizzi was in the harness/ropes voluntarily or not isn't the issue, the description of Lizzi having a seizure due to lack of oxygen and then Kat seeing the prone position with feet facing inward and hands/wrists pulled up seems quite reasonable.
I don't see that there should have ever been a disagreement over marks on Lizzi's neck, the statement to the defense makes clear there were ropes in her neck area being pulled (as well as the harness strung so it would decrease oxygen if her head is moved forward) so I think in either case marks would be likely to be seen on her neck, so for me that is a waste of time trying to prove/disprove that.
I've been thinking about the bags, why one and moreso why two; those bags are rather thin and see-through, and two would be necessary so not to be able to see what they're covering. If Kat was annoyed at seeing Seth with Lizzi (since Lizzi was supposed to be her 'dark haird lady') she simply didn't want to be able to see her face any longer, discolored or not, it wasn't the face of Kat's dark haired lady, it was the one who had had sex with her man.
