Excellent, ColemakDH is up and running now.
I had to install and could not just run Dreymar's Big Bag of Tricks as GNOME3 overrides setxbmap.
Though this solution is more elegant now that I use the system to configure my layout and not a startup script.
I wasn't done there though. In the initial Curl-ED, my 'D' key was at the B position and the bottom row was unshifted to the left, not how I wanted it.
I went in manually, in the /usr/share/X11/xkb/system/colemak file, adding the bottom row letters to the Dbg cycle that is (Z X and C).
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Though these couple of days showed me that the DH mod is true to vanilla Colemak, since I could type relatively quickly if I stayed mindful that DH were annoyingly and uncomfortably in the center. There was like a 95% retention between the two so that Colemak can save me in a pinch where ColemakDH is unavailable.
The past twenty minutes show me why I love DH though. It's like adding Chocolate to Milk.
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Thanks again guys.