Thanks Frederick. (And thank you for the series of recent updates to W3TC.)
I found a better plugin, that works with W3TC, here:
http://ww.wp.xz.cn/extend/plugins/yourls-link-creator/
Yes, but should the code be placed “after tracker initialization” or “before tracker initialization”???
Found this in another thread. In Options set sort order to Custom Order. The button should then be visible.