Hi Phil
Congratulations on making the step from footlocking to SRT - A wise move and your body will thank you for it in a short space of time. In terms of honing a system for bio-mechanical efficiency, we have a few pointers that may help.
I have shown your video to Davina - my wife and very experienced remedial personal trainer, who helped nail my efficient SRT setup, and rid my body of the 'footlocker's twist' (no mean feat!), that I developed over a 10 year intense period of competition, comp training and daily use.
Rope walking systems can be optimally efficient in a bio-mechanical sense when used with a chest roller. This is because they keep the body upright without pulling through the shoulders, enabling quick short steps without wasting energy on stabilising lateral sway, keeping the spine and hips in alignment. In this respect, your video shows you still using a substantial amount of upper body work to help keep you upright, and you demonstrate a lot of pelvic sway.
We believe the Frog to be the most bio-mechanically efficient AND practicable system for most ascents. This is because the body is in line and powered by both legs at the same time from their mid range.
The Chest ascender and harness are key here to efficiency. The chest strap being tensioned when sitting to hold the body upright without relying on the arms/shoulder power (though the arms are still required for stability). The harness needs a low centralised anchor point to avoid ascender clash. Smaller climbers will benefit from replacing the Petzl 'Ascension' with the 'Basic' for example.
The harness leg straps should be set snug, so there is little movement when sitting in the Chest ascender. The footloop length is very critical to efficiency.
I use one footloop and a Pantin, known as a 'Frog Walker' system. This enables me to align hip and knee by positioning my feet shoulder width apart. This makes ascending against the trunk simple by allowing a 'straddle' technique. It also means when I get into the branches, I can stand on branch with one foot and rope with another, or pull on the ascension with both feet on branches, or shunt up the ascension and climb with hands and feet on branches, all the while being supported by the Croll, so no fear of slack or a fall at all.
If you get the opportunity to try a Frog walker system, please do. You'll get the jist of what I'm on about.
I hope you see the ergonomic angle we're coming from. Keep up the innovation!