Are you sure you are not pulling to much air out of your restaurant with two hoods. The easiest nonprofessional way to find out, is to make sure all doors and windows are closed and then open a door slighty and feel how much of a breeze it produces. If you feel a breeze, you have negitive air pressure inside your restaurant.
Air should blow out of your restaurant when the door is opened.
That was my experience. My hvac guy slowed my exhaust fan down and it made a big differance in keeping my restaurant cooler