I haven't directly compared to Equilibrium, but I noticed the E modes on Softube 9000K, bx_9000J and SSL Native Channel strip are all WAY wider than most 4000 series E emulations.

Maybe its closer to the 9000 take on an E series EQ? I think quite often, its the gain/Q proportionality, and overshoot/resonance that they'll determine the difference of the various SSL EQ's. Definitely interested to know what's going on with Equilibrium - the shapes and behaviours across the bx_consoles have all appeared pretty much as expected to me.