I have a lot of crossbars laying around. My current mounts are from multiple different Yakima mounts. Designed some gutter mounts that will accept Yakima bars. These mounts will have a set screw allowing the bars to slide from one side to another if needing more bar on one side. I have cut 2 48" bars in half and will use those for cross supports. The brackets for the cross supports will be modular so I can move them easily for different setups. I'll post some more pics this evening, but here's a teaser of the gutter bracket. My buddy drew it up for me and waiting them to be cut and broke.
https://imgbb.com/

https://imgbb.com/