Sound System Connecting Advice Please

[CCD 0]

Hi guys, I'm new here and quite new to the mobile DJ world (a little over a year)

 

I would like to get some advice regarding connecting my powered speakers please. (XLR leads)

 

Firstly, is it better to connect to my tops first then to the subs or vice versa or does it make no difference?

 

Secondly, is it possible to daisy chain my previous 600W tops to my current 800W tops for extra oomph or is that a bad idea?

 

Finally could someone please explain the button on the back of my sub woofer? It has two setting. One says 0° and the other is 180°

 

Thanks guys