The quickest way to IAH is the 737. You will not be able to hold the 756 in IAH for 4-5 years as it stands now.
The last A320 pilot in IAH that was awarded it is currently 11,400 out of 12,400.
The last 737 pilot in IAH that was awarded it is currently 12,100 out of 12,400.
The last 756 pilot in IAH that was awarded it is currently 11,000 out of 12,400.