The Caboose (legacy) for the Radwagon "1-3" seems to be out of stock and uncertain if/when it will be sold again.  Superknuckle has a version for $30 more that appears designed for Yuba but they advertise as compatible with the Radwagon ("Modified for Legacy Radwagon (pre-RW4)(extra mounting holes)").  Has anyone had experience with this?  Thanks!
https://www.superknuckle.com/product/adjustable-monkey-bars/22?cp=true&sa=false&sbp=false&q=false&category_id=9