What a great video. I think you've certainly demonstrated the capabilities of each instrument.
I owned a Modulus Q6 until about 6 weeks ago. I currently own a Roscoe SKB3006.
I think, from my experience, and your video, I think confirms this. That the Modulus is a very 'neutral' sounding bass. I used to use mine in a similar way to how Steve Lawson uses his, swamped with effects, to create soundscapes.
The Warwick sounds best for the rockier part, it has a sound that cuts through better than the others. The Modulus seemed to get lost somehow there.
I've never liked Spectors.
I mostly play jazz, and my SKB3006 seems well suited to this. It has jazz pickups, and a birds-eye maple fretboard, so it's quite a bright sounding bass.