Generally with these things its trial and error. You must ALWAYS mark where an adjustment is BEFORE moving it. This way you can put it back to where it was if it doesn't make a difference. This applies to all adjustments on anything ie wires, adjustment screws etc. On this issue im pretty sure that with hydraulic adjustment screws turning them into the barrel compresses oil, so will increase tension and vice versa for the other way. that's the way I have generally go but I always mark/measure(the screw length from the base) so I can put it back if I need to. Doing this and testing is the easier way to find out if its a door check issue. let us know how you go.
Ps. make sure you haven't got something stuck in the car door track. I've done that before too!!
