I ported Nuttytree's Smartthings DTH for the GE 14291 Z-wave Plus Switch a couple of weeks ago. It has been working well for me. It supports double-tap and also reports physical / digital events correctly.
I just posted a link to it in this post.
I'm glad to hear that Hubitat may add native support for double-tap for the GEs. This was my first port of a driver or app from Smartthings; it was a fun project in any case 
