Pie and I had an arena session today. Although it was in the mid 50sF, the wind was blowing hard - 25-30mph and it wasn't really very nice out. Pie and I managed though, and worked hard on our softening work at the trot. Once I managed to get a good, forward trot - sometimes a challenge with Pie - we worked on 3, then 7, then 9, then 11 soft steps at the trot in both directions, with some rest breaks in between. He'll now reliably give me 11 soft steps at the trot in both directions - when he really does it right I can feel his stride lengthen and his back lift. It's still hard work for him physically, so we stopped after several repetitions of 11 soft steps in each direction. It was easier for him to the right than to the left, which I think has more to do with how I weight my stirrups than anything else - I tend to more correctly weight my left stirrup which means his work to the right is easier, while my right heel tends to go down too far and my toe tends to come up, which I think doesn't help him out when we're tracking left. I also suspect since I switched my right and left leathers that the right one may be a hair too long - before I get on next time I'll check this out.
The next objective will be for him to consistently soften at the trot. And we'll be working on getting soft halt/walk/trot/walk/halt transitions and then move on to cantering. Pie progresses!