Little foot note (pun intended).
I have returned to practice in the Feiyue shoes I bought for the princely sum of $14.99 on Amazon. I decided to persist with the slightly rounded sole. Finding balance in these is slightly more difficult than in Converse Chucks, but in the end it will aid balance. The Feiyue are lighter and there is more a feel of the ground. More flexibility too.
Here's another footnote. I had read that the Feiyue were probably fakes, with the genuine article costing much more. Since then, I have seen a number of photos of Shoalin monks training. As far as I can see the shoes are the same. So I think the fake story was, well, a fake story. Well I never!