Still cant get it up??!!

Ok, so Ive asked this question before, and Ive gotten mixed responses. I have 4 valves on my b/d 98 s-10. All the valves were in the back. The rear gets up fast, but the front is hella slow. So I moved the lift valve closer to the front bags in the engine bay, and left the dump still in the rear. Im all geeked figurin' it would atleast go a little faster than before, but its the same. I know theres alot more weight in the front, but dam, whats up. These are 1/2 inch valves and 1/2 inch hoses. And also, Im not running a guage for the tank, but how long do you let your compressor run before the tank has enough pressure to lift the front fast. The rear lifts fast with little air. Help, I need it. Sorry for the long post.