What is your favorite sling design/material/length for distance or slinging lead

4mm round braid cords have been my overall favorite sling cord for all purposes for remarkably long now (considering I change between sling kinds and types A LOT, I always return back to these if I can)

https://youtu.be/DZ4XJ5qnNbU
In the video I used a 30" paracord sling with a pouch cut from a leather belt, but when I briefly revisited it off camera with a UHMWPE ("dyneema") sling (of the same length), the results weren't wholly different. The only difference I noticed was that I could throw bigger stones further with the UHMPWE sling, but I think that is down to better release knot grip/ and or more aerodynamic and efficient cords + pouch. What I take away from that is that it's the length that determines max velocity, and any added sling weight/drag effects the efficiency of the sling. For example say the light sling throws 50g projectile 70m/s and a heavier sling throws 50g projectile 60m/s but can throw get back to 70m/s by dropping the projectile weigh to say 35g. I believe there is a velocity cap for a given length, and so while the light sling can throw a 50g projectile 70m/s, it won't throw a 40g projectile any faster. I also think there is an optimum projectile weight + sling weight combination for the biomechanical motion, because if a sling is "too" light then a projectile that would feel fine in a heavy sling may  feel less wieldy in the light one. This is purely conjecture based on what I've found, and is unsubstantiated by any hard data, but there we are.
My ideal long-range sling would be the same model I use for accuracy shooting (cortaillod), but 30". I say 'would be' because I haven't finished it yet.