I tried everything to get a Scubapro manifold as smooth and easy as my MDE ones.
Even things that were not mentioned here like cutting grooves in the valve threads to help equalise both sides of the valve.
It got a lot better than stock but was never as good as the MDE straight from the box. Eventually I got fed up with it, punted it on ebay and bought another MDE to replace it.
In saying that I am not a bit fan of scubapoor kit, too much of style over substance in its construction...........