The Mesa Dual Rectifier is LOUD!!!! FREAKING LOUD. Mesa somehow manages to squeeze extra horsepower out of their tube heads.
Which Dual are you planning on getting? (2 channel, 3 channel, or 3 channel Reborn?)
On my 2 channel, once I get the volume up to between 9:00 and 10:00 (2 - 3 on a typical 100watt head) the tone opens up, something I attribute more to the speakers than the amp itself. If you are playing heavier music, you can turn up the gain for low volume playing to maintain saturation for your tone. If you like lighter tones, you need to crank the amp more to get that crunch and breakup. (running the gain below 11:00 on the modern channel, for instance)
You can run the volume until about 12 noon (5 - 6) on the Modern Gain channel before the power tubes begin to distort heavily and the tone turns to a soupy mess. The best crunch tones are found by running the power section just hot enough that the tubes start to purr slightly. Like barely edge of breakup.
The real 'problem' volumes are under 9:00 or under 2. That is when the tone is thin and really buzzy. I would definitely NOT recommend one of these for bedroom playinG!
If you get the Reborn head, you can do bar gigs with 50watts which should get you more crunch. What you can also try is running maybe a 2 x 12 or a 100watt Marshall 4 x 12 (lower efficiency speakers) for those bar gigs, depending on what you need. With a Dual, you can also pull out a pair of power tubes and a rectifier tube to run your amp at 50 watts in the case you don't have the amp with the half power switch. Do keep in mind you will have to 'reset' the speaker output to compensate for the missing tubes. You connect 4ohm output to 8 ohm cab instead of 8 ohm output to 8 ohm cab in this instance.
If you tell me what style you play and what your needs are, I can better answer your question. The 2 x 12 for small stuff and the 4 x 12 for bigger stuff is a great option, and don't forget the earplugs.
As for pickups, high output mid boost and bass cut pickups are best for this amp. They tend to tighten up the tone and add more 'cut' to it.