Iowa Bifold and Hydraulic Doors

1 I am working on a project in Iowa and I think your hydraulic system looks like it has everything I need. are your cylinders single acting? And would you be willing to sell just the hydraulic power unit? And how are you ensuring that the door goes up evenly? if I had a door, and one side was 10' longer then the other can your system still keep this door opening and closing evenly?