I gave up trying to fix sleep for now. The problem I was getting was a complete loss of the running session (including unsaved work) when coming back from sleep. I applied some configuration changes that seem to correctly put Windows into hibernation mode instead of sleep, and although there are some things which aren't as reliable in hibernation as they are in sleep, it's better than just losing everything unexpectedly. With SSDs I don't really mind the increased delay when resuming if it means I don't lose anything.