If you are using a Mesa M-2000 there is no reason for you to be lacking any mids. There are two separate preamps with four different EQ sections on that amp. I use all kinds of different basses through my M-2000, including some basses that have plenty o' mid-scoop, and I've never had a problem dialing in some mids. Including the preamp on your bass, that is 5 different EQ sections for you to mess with.
These are the base settings that I use.
Tube preamp: I bump the low-mids with the graphic EQ. I center it around 180 and boost the frequencies next to it a little and I keep the rotary EQ flat. This gives me that thick, R&B tube tone.
Solid State: I boost the high-mids right around 600 and the frequencies next to it and will add some bass with the rotary if I feel I need it. With this setting I get an aggressive, more modern tone.
By mixing these two settings or just switching between the preamps I've never had a problem. The SWR is a very mid-scooped cabinet, but you should be able to put some mids back in with the EQ no problem.
Michael
I'm in a stoner rock outfit....so I mostly use the FET side for cleans and the blend setting for big dirt tones.
I tend to dig a fat, almost dub like clean anyway.......but the stingray just sounds flat, rather then round.
For dirt, I blend the FET and High Gain channels. Gain cranked up and treble boost on. knob EQs set to noon, except the bass which I back off to 9pm. Then I adjust the sliders to boost the low mids and upper mids.
To me, the 3 sliders farthest to the right on the EQ don't really do much within my rig.
Which is why I have a hard time dialing in a more present or treble rich tone.