Just grabbed some dinner and had been thinking about this. Dervy - We have a 20 min parse where 238 Spell Speed did not grant Iftit even a single additional Burning Strike. That is longer than any encounter actually lasts. While it really isn't looking like Spell Speed impacts the pets at all, even if it starts to creep up at even higher spell speeds, the increase is going to be so small, and the pets are just a fraction of SMN damage. Any impact to numerical weighting is going to be negligible. I think that you can proceed with weights as if speed doesn't effect them.

That being said, do you have the data you need from an actual damage perspective on the pets (INT/DET on how hard they actually hit)?