I can relate to both descriptions of Phil's 80s tones. I think it took a while to dial in the graphite thing, and also it sounded like there were experiments with strings. There were times when the low end was intense, but only during the bomb drops. A lot of times, the bass came across as kind of clanky, like round wounds with the action too low. But, I would imagine it sounded very different on stage. As time went on, I think there was a bigger and bigger disconnect from the stage sound to the room sound. Why that was, I can't say, but maybe a lot of factors. Their PA got more and more high tech and capable of really changing the tones of the instruments drastically. My guess is that Phil's perception of his tone hasn't changed all that much over the years and the biggest difference is how it was presented to the room.
I definitely agree with Stephen's assessment of how they interacted. My personal view is that having a much busier keyboardist with a more limited vocabulary was a big factor there.
I keep trying to play my Modulus at gigs, but it's just never as satisfying as the Starfire.
It also seemed that as the 70s wore on, he got quieter. At a certain point, the bass stopped carrying the mix.
Weirdly, that's all such ancient history now!