Assuming your panels have bypass diodes as most do, they bypass the under performing panel sections to prevent current from stopping.
The other concern is paralleling unequal panels in series. When paralleling they will match your lowest voltage. You said that other strings will be 6-9 panels if you can make them 6 panel strings and make more strings that can be placed with no shading then that would be best.
The lower voltage from the short string will have a higher impact on decreased current then the partial shading. If making more strings, then make sure the wire size from the combiner to the controller can handle the amps.