Action Sports Cartel

Hi, I am trying to get my head around the durations quoted for elinchrom Rangers. I remember a couple of posts either here or back on W&W, but not really sure what conclusions they eventually came to.
I understand that using an AS pack, the B output (433Ws?) is meant to have a quickish duration - is this only with a A head though? I am trying to work out whether you can still get good action stopping durations using a combination of an S and an A head, the A on the A output and the S on the B output.
When I've had a chance to play around with one before I seem to remember that using an A head only on the A port produces durations that are only just good enough to stop action - would I get better results and lower durations splitting the power over two heads, even if one of the heads was an S head?
Also, would I get better durations by using and extension cable to reduce the power rather than turning it down on the pack?

I hate the fact that it's so hard to find real information on these things, too much deceptive t.5 duration specs.