ULTRABRA
if I have FX on the Strings Bus, they will now also effect the reverb.
In addition to assuming you would want to continue using the Reverb bus universally for other tracks, that's another reason why I suggested using a pre-Reverb bus to collect the sends from the string tracks.
What I meant by that is you create another bus that
outputs to the Reverb bus and call it something like String Sends. Then group its volume with the Strings bus volume, and re-assign the sends from the String tracks to this bus.
This way you still have individual control of the send volumes but their contribution to the Reverb bus is tied to the output level of the Strings bus, and the Reverb bus still returns to Master in parallel with the Strings bus as it should and can still be used by other track sends.
I think this solves all the problems.