I'm no expert (obviously, as I have MAG 300 + MAG 2x10 + MAG 1x15), but I'm of the opinion that there are so many influencing factors involved before the signal gets to the head, that I would happy to play through any head/cab combination, and adjust the characteristics to suit.
Pickup type, pick-up positioning, pick-up blending, fingering type (attack etc), fingering position, bass tone pot, (and in my case) graphic eq pedal etc etc. I can adjust all of these to get exactly what I want to hear in any given circumstance (rehearsal, busy pub, empty pub, hall etc). I can make my fretless P sound like a Ric, and my fretted J sound like Macca's Hofner. I've never felt the need to agonise over the amp controls or features (although the Ashdown's built in sub-harmonic feature is pretty good).
Just my non-expert opinion, but if the Ashdown is 'woolly' given what it is being fed, then feed it something else. I'm pretty sure I could make an Ampeg or Hiwatt or whatever else sound 'wooly' if I wanted to.
Just all seems a bit anal to be fretting over head/cab combinations as if we all play in acoustically perfect laboratory conditions (which I certainly don't).