@Ez E not sure this has been mentioned, if you really feel like you need an adjustable harness, get the Halcyon with the cinch system, because when you realize that it isn’t needed, it can easily be removed and it’ll then be identical to the system which does not come with it, no modifications or adapters needed, in fact the cinch is the modification and adapters to the simpler system, this will be much cheaper on the long run.
And if you end up using the cinch, well, then you’ll have the better option anyway.
Something else I think hasn’t been mentioned, on the Halcyon system, it comes with the back pouch storage system, one of my favorite features, you can easily store a big 6’ SMB there and it’s not like you’re even carrying it, super convenient.
Some people like the deluxe harness pad, I didn’t care for it, like the cinch, after a while I removed it all, and the padded version of the back storage pack is a bit harder to store the SMB btw.