If you are using the Treemagineers Hitch Climber system seriously consider splicing your termination (the rope-end attached to the top DMM Ultra O).
As you can see in the image below your friction hitch can 'release' unexpectedly if it catches on the edge of the termination (rope-end) knot. This situation can be exacerbated when you use a spliced e2e friction cord (as opposed to a stitched e2e friction cord).The two splices in the friction hitch create a stiffness in the cord (often up to 100mm from the eye) which causes it to set quite differently to the Ocean Polyester stitched e2e tested for the Treemagineers CE Climb. That's why some of the top climbers prefer stitched eyes (or even a knot) over a splice on their friction hitches - to ensure the friction cord 'legs' wrap tightly over the Hitch Climber fairleads helping to ensure the correct setting of the friction hitch on the climbing rope.
Most 'factory' lengths of climbing rope sold by Treetools include a terminated splice but plenty of rope is sold in custom cut lengths where splicing is left up to the end user. Often a knot is favored over a splice (due the added cost of the splice) but if you are intending to configure your system as per the Hitch Climbers Guide to the Canopy invest a little extra in the termination splice - if only for peace of mind.
Download your copy of the Treemagineers Hitch Climbers Guide to the Canopy and refer to Page 15 which shows potential misconfiguration situations. The hazards of a knotted termination interfering with the correct hitch function is first off the rank!