It sounds like you pretty well have it figured out already. What we are discussing is quality of light. I have used many light sources and they all have different qualities of light. I have a large softbox that when just outside of the frame( outside of seeing through the viewfinder) I didn't really like the light. When farther away it is better. When I used the medium softbox I like it a lot just outside the frame. I have a Halo Mololight that I really like a lot, same thing close up, just outside of the frame, however it is tough to feather because it will flare back in the lens. I have a Mola light, same thing, I like it close up. I almost always feather the lights to get the wrap around effect, thereby lessening the light falloff.
I use monolights because you can place the light where you like the quality of light, and then dial in the f stop that you like to use. I also keep my subject far enough from the background so that neither bringing the light closer nor father from the subject affects the background. On some power packs with a couple of heads you don't have this option and you have to move the lights to get what f stop you want. Also probably every different company's lights also give different results in the same light modifier.
Anyway it sounds like you know what you are doing, so I think you just have to experiment with each light source and find what you like.
Hope this helps,