I can't say I got all the answers here as everyone seems to like different things. There are tons of ways to do a LR stack, personally I tend to not really look at them as progressive or digressive in a normal sense on their rate. I sort of have my own way at looking at them, which is sort of hard to explain but in my mind it makes it easier to make sense of it all and figure out what the car wants.
People get so caught up in certain things, but miss the big picture. This goes back to what I said in my first reply to you: That a single linear spring on the LR behind generally don't act linear at the wheel. With that being said, here are some things that can happen (I'm not going to overly explain or get into this very far)
Example:
Car A has a 87.5# rate spring (say a 175/175) and has 300# of extended load at full droop
Car B gas a 87.5# rate spring (say a 175/175) and has 200# of extended load at full droop
Car C gas a 87.5# rate spring (say a 175/175) and has 100# of extended load at full droop
I'm keeping the rate the same for simplicity, Typically if you change nothing on the car but just change the adjuster on the car to vary the open load from car A to car C and anything in between, you'd expect the car to stay up better with more open load. This is basically because there is more tension on the spring to over come for the car to fall. While this is generally correct, without taking into the progression/digression of the LR suspension on the spring rate the wheel sees it's possible for this to happen:
Car C even with the least amount of extended load could easily be the hardest to make the car set down.
So without taking all this into account you may not be accomplishing what your trying or making it harder on yourself.