It's been a while but we're slowly getting back into it.
A few days ago I took an old sock (tucked into the waistband of my shorts to help with scenting) and Tali's giant rope bone to the footy oval and we did a couple of easy tracks to see if he remembered how to do it. He had exactly no trouble remembering how to do it, and the fact it was a black and grey sock on green grass probably didn't hurt. He can at least use both his eyes and nose at the same time and even managed to find it when I draped it over the fence above his head.
Today we did three slightly longer tracks on the bush walk. The first one was an easy drop on a tuft of grass by a citrus tree. The second one was on top of a log that gets used as a ramp by BMXers. The third was partially hidden under a fallen tree and I laid a bit of a horseshoe trail away from it. Tali had a momentary confusion as he was undecided as to whether to follow the trail back around the horseshoe I'd made or to cut straight back where he could probably smell the beginning of the trail might be, and opted to follow the trail.
I need to make an el-cheapo tracking lead (trigger clip + about 10m of light rope) and see if I can find a harness that will fit him without burning my wallet. He was tracking off lead which was fine while I had his attention and he remembered he was looking for something but on the third track there was the distraction of a dog barking in the near distance that may or may not have been in the park somewhere and I had to call him a couple of times to refocus him. Will do a few more tracks with the sock and then I think I might start bringing my tracking partners to play doggy hide and seek again.