Id like the SEQV4 to send a midi message when a track selection change is made.
It doesn’t matter what so long as G1T1..G4T4 are each a different value.
If it were possible to assign a particular value to each track selection, I suppose that would be ideal.
Why do I request this? (I’m glad you asked! 
)
An NG based synth editor will address the synth multi part# used in the selected track, issuing a SysEx dump request.
This updates the control surface state with all the synth parameter values in the newly selected part.
The SEQV4 feature: “SelTrk” routing ensures that all the CC controls from the synth editor are transmitted on the midi channel of the selected part.