Hi,
you would just connect the second tail servo to a free physical output on your VBar NEO, and edit it's Macrocell so it's Channel and has FC Elevator as an input (same as the original output has). There, you can adjust the direction and travel, and that's that.
In case you have issues with synchronizing the control surfaces (because of geometry, linkages), you could even put a curve cell in between to match the extra servo, or put curve cells in between on both, to be able to adjust both.
Kind regards
Eddi
Born to fly ...
forced to work.