Hartke HA3500 4ohm load?

This is my first stack and have a question that probably has a very simple answer. Recently purchased a Hartke HA3500 (double height wooden head), the hartke 410XL and 115XL. To achieve a 4ohm load do i run each cab to the separate 8ohm outs or run one out to one of the cabs and then run the extension out to the other cab?

 

Thank you Gluvhand!