Hello Jack,
I believe adding the ^FWR command via a Print-Control command node in your SF is the way to go. But you need to re-set the rotation to "normal" after your "to-be-rotated" field. Here is what Zebra's ZPL2 documentation says about this cmd:
"The ^FW command only affects fields that follow it. Once you have issued a ^FW cmd, the setting is retained until you turn off the printer or send a new ^FW command".
So you need to somehow achieve that you send a ^FWN after your rotated text which will set the default rotation back to "Normal" = unrotated.
Best regards,
Alexander