I'm a bit late (2 days
) to this conversation, but I'll post my thoughts in case they're still of value to you.
I don't gig regularly anymore and when I do I'm usually on backline gear. But back in the day I used a combination of Ampeg amps and cabs. Here's what I found in my experience:
* Nothing compares to the sound of a P bass through an SVT and the 8x10 cab. The way it moves air, the way it punches, etc. I used this combination whenever I played 500-1200 capacity venues with an alt-country loud rock band. We almost always had help to move the gear at these larger shows, so the only pain was making sure we made room for the larger cab in the van/truck.
* When I didn't want to move the 8x10, I ran the SVT through a 4x10. It sounded good-to-great. But I quickly got tired of moving the SVT, which in the flight case had to be close to 100 lbs. I started running an SVT III Pro into the 4x10 and got the sound I wanted at a fraction of the weight.
*
Touring I used the SVT III Pro and the 4x10 to save space and my back.
*
In the studio I always used a B15 + direct. Never any of the SVTs.
Conclusion: The 8x10 is AWESOME but big and bulky. Try out the SVT III Pro through the 4x10 (or 6x10, although I always thought if you do the 6x10, might as well do the 8x10
). I was able to get a sound I was very happy with using the III Pro and the 4x10 and my back thanks me. So do my bandmates because we didn't have to get a bigger van.
Hope this information helps.