If wires can be run between the two panels you could do something like this: Determine which panel has the greater usage during daylight hours. Install the two CTs at this panel. From the other panel, loop the circuits that constantly have most current draws through the CTs. Use proper phasing and polarity on each circuit. May require larger CTs. Mini splits or inverter ACs would be about the best candidates. Pool pumps also would be good. Computer, video game circuits etc. If you grasp that concept, clamps on the greater usage panel might not be the way to do it. Maybe you should place the clamps on the panel that doesn't supply mini splits, pool pumps etc. Loop them. Conventional heat pumps are a toss up. When they are off, they use next to no electricity, leading to a situation where solar might over generate what is being used. The solar may be wasted. Having mini splits may be a major advantage if two panels are involved.