Yep, just had a look and there were only 2 horses in the cup which won races to exempt them from the ballot - Growl and Sphenophyta. Apart from that, all of the other positions were decided by comparing their handicapped weight to WFA.

The two horses you mentioned, Grand Zulu and Testafiable are both 4.5 kgs below WFA, whereas Zipping is 6 kgs below WFA. If Sphenophyta had only finished 2nd in the Turnbull instead of winning it, he would have missed out altogether as he's 8 kgs below WFA. Same with Growl. If he hadn't won on Saturday he wouldn't have made the field either. He's 7.5 kgs below WFA.

As I said, far too much rests on the weight allotted to each horse by the handicapper and that is mostly based on old form. They need to allow many more qualifying races to allow the horses in the best form to get in the race.