Congrats!
I bought the WD the without hearing it as well. There was a lot of new-to-me technology (HPF, passive mid control, power amp damping) that took some time and use to understand. The parametric EQ is still a bit daunting to me, but the user setting examples in the manual were a great starting place. Most of the features I didn't understand at first only made since when I had the amp turned up in a louder, live environment. I would never hear some of these controls with headphones or playing solo. Boomy tones on stage are calmed by HPF, instrument presence adjusted by passive mid control, attack (cone quickness?) are controlled by power damping... to me, all that stuff became understood in the mix at performance volume levels.
A good example: One of our singers whipped around during a recent sound check and demanded that I turn my bass DOWN. Granted, the elevated stage was large and the FOH guy had me up in the subs. I simply dialed the high pass filter up a few degrees and it removed the rumble from our feet. I also rolled the passive mid back a touch and my pbass mellowed. I didn't adjust the EQ or volume. Everyone was happy again, especially me.
Oh yeah, don't try to explain any of this stuff to non-bass players. Waste of breath. Well, monitor engineers understand it but likely won't be impressed. LOL
One more thing, the controls on Mesa amps are sensitive. Do small adjustments instead of big sweeps when dialing in your tone.