Hans yes this is the valve:
http://www.festo-didactic.com/int-en...i4xMjQ4LjY2MDk
Hey Don! you are right! what i do is i bypass all restrictors when i retract up (to alow more flow as you discribed) !
but i dont think if you fit a restrictor on the vent of the valve will alow you to have no restrict when you retract up the gear
couse up or down move
air comes always out from the vent in one direction

...so you still cant avoid restriction while retract up?