Griff: Aron uses Autolock buckles. You can order them from Kifaru and a couple of other places.
Yes, you have to actively press in a section to release the tension on the Autolock buckles, rather than the standard ones, which work loose over time.
The key thing is to order both male Autolocks and split-tail females (you need 4 of each for an AGC) - the male Autolocks do not fit into the existing AGC female buckles. An easy way to remove the existing females is with some strong sidecutters - it's easy to just push the webbing aside and cut through the buckle, rather than mess with a saw or Dremel-type tool, which I've also heard of some people using. It usually only takes one or two squeezes and you're done. (Incidentally, this is how Mel recommended removing buckles on an old Kifaru video.)
From memory, Aron mentions swapping out the buckles on a couple of Gritty Bowmen podcasts ... the main one is an early gear run-through, but there's little detail given and no real visuals. Just order the buckles, use some sidecutters, and you'll be right.
Oh, and it can take a bit of persuasion to thread the AGC webbing through the male Autolocks. Again, a tip from an old Kifaru video: if you can poke just a corner through, you can then use needlenose pliers to pull through the rest.