No fikar auto bro
I guess that the general conception of GS having higher top speed than CG is with stock skinny tyre and rim only.
With this bigger rim and 90/90 tyre at the rear, the best i can do is match CG speed. that's it.
Even in this incidence, if i would have been riding alone, i could have pushed my speedo to 115Km/h which would have been just enough to keep him behind me once i overtook him.