The technology gains the extra velocity from higher pressure, NOT more powder. If fact, to make it work with shorter barrels it's often using faster burning powders (ie potentially less powder). As an example, Winchester Staball 6.5 powder reaches max pressure of about 64k psi for me at 45.8 grains. Varget, a faster powder, produces nearly 94k psi at the same charge weight. I must back it down to 40.4 gr to see the same pressure as the Staball. Or, at about 44.0 gr of Varget I'm hitting max pressure for the Peak cases.
Bullet weight will impact recoil, thus your preference for the 6.5 over the .308. However, I don't believe pressure will have the same impact on recoil. You'll literally be shooting less powder for more velocity.
All the guys who say what does it do that my current gun/ammo won't do in terms of effectiveness are looking at it from the old school viewpoint. Used to be you had to justify a new gun. Now, you can get more velocity, same or less recoil, and keep your current gun. Seems like a no-brainer to me. I can't wait to try it in my daughter's 16.5" Ruger American Gen 2!!