If your having trouble getting needle valves to work right, I would recommend one 1/8" wheel collar on the "up" or "retract" air line and a basic valve. Put a dab of pink thread locker on the wheel collar set screw, test the gear, and adjust till happy. You can pretty much forget about it after that as it is very reliable
Putting the restriction on the "up" line will help slow the extend cycle once the gear unlocks. On heavy gear, especially ones with long legs, there is a lot of weight hanging on the up lock. It takes a bit of pressure to overcome this and unlock the gear. Once the gear unlocks, they want to slam down, but it still has to push the volume of air out of the other side of cylinder, past the restriction to extend. On problem gear, I like the wheel collar closer to the air cylinder
I have found this setup really helps smooth out the extend cycle
Just my 2 cents