Going back to my more natural pronated DSX technique, I thought I go back to the source with Speed Kills/Speed Lives which was the first instructional DVD I went through as a teenager. I was focused a lot on the sweeping in it at the time because the descending sixes runs came easier to me, it’s a bit messy in a couple small spots but feels pretty solid.
You can see pretty clearly how I pronate my forearm when descending.
It looks like it’s zero effort to you whatsoever 
Good job!
It’s interesting that you appear to pronate more as you descend to the lower strings? If playing on the lowest strings, is the anchor point the thumb heel only, or pinky and thumb heel?
The only time I ever anchor with my pinky or ring is during some extended sweeping patterns, and I feel like there it’s inconsistent - maybe it’s nothing more than needing a bit of a fresh feeling on what I’m playing to get myself to focus more, but I think anchoring with the fingers can give a bit more evenness to economy and sweeping.
For alternate picking, if I touch the guitar with anything besides the palm (and I guess the forearm resting on the body) - it makes me feel “trapped” and throws me off. So I’m just anchoring with the palm heel.
It really does feel like very low effort once I get the pattern under my fingers playing this way, compared to working through crosspicking or USX. I’d say Gambale picking probably feels kinda natural to me as well, I haven’t focused on it a ton, but I gravitated some toward two way economy as a teenager, once I managed to get sweep picking somewhat under control. I’m trying to study Rick Graham on that front because he manages to do it with great dynamics, which is damn hard to do.
I think you have a similar looking setup to Frank here also, which might be why it feels quite natural. I often see him doing fast runs where he appears to pronate also.