Thanks all. It seems like things may have improved since then for 24 hour TWOVs (based on more recent data points). I don't think it's worth paying for a visa since I've already been to Shanghai a few years ago. I'll book a room on ctrip and plead my case with a 9:15 hour layover, with the understanding that I may not make it and end up in that lounge shower after all! Thanks moondog for all the great suggestions, which I'll use if I make it to the other side.