Change max width breakpoint for tablet (portrait) layout

Hi all,

I’m developing this landing page and would like to increase the portrait breakpoint to 1024px.

Notice how the page looks good here on tablet portrait mode with 600px width: http://quirktools.com/screenfly/#u=http%3A//www.homesinc.com/i3/&w=600&h=1024&a=25&s=1

But looks bad here at 768px width: http://quirktools.com/screenfly/#u=http%3A//www.homesinc.com/i3/&w=768&h=1024&a=22&s=1

How can I make the grids break at a max with of 1024?

Thanks for all your help!

Dave