Why not bypass the controller on the portable panel & feed it into the input of the SC2030?
I have 195 watts on the roof that feed a Blue Sky 30 controller & added a port to the trailer that feeds the input to the Blue Sky controller. I use the port to connect a 160 watt portable with an additional connector that bypasses the portable panel's onboard controller. A Trimetric 2025 keeps track of total in & out for the batteries.
My reason was I wanted the Blue Sky controller to show all the solar panel current & amp hours - If you don't feed all the panels into it, you won't have accurate readings of the amount of energy collected. Also, if both panels don't go through the TriMetric 2030, that info will also not be accurate.