Gary Highway

Travelled both in full a few weeks a ago Dave.
There is a lot of spinifex at the moment, not sure how much will be there mid August.
The stainless mesh I fitted between my nudge bar and upper shadecloth worked good keeping it out of my cores up front, but underneath it was a good clean every few hours as my trans cross member acted like a guillotine and packed above my transfer case bash plate very efficiently, like a hay bailing machine.

Lake Cohen was fine and had a good amount of water, but the OSM track was all fine to drive (on the upper lake flats, and coincidentally provides an excellent spot to clean out spinifex :) ;)

As you guessed, both tracks are slow, as was Connie Sue, lots of what you mentioned, and encroaching vegetation.

We saw some awesome sights along the drive, most spectacular where the actual Breaden Bluff caves, and if you are going that way, Neale Breakaways.

Enjoy.