Quick update for my own memory. Missing from my DXG as it stood after my original post: active content. This post had me sorted:
(though you may want to hit post #354 since it looks like there's a slight update)
I ran it without any of the 2.5.8 series stuff, my bad for not having a backup. Maybe I'll find that and improve it...
All of this was needed to show the new launcher to work on the DXG. It does.