if you look at the original ssg by Bob Sterne you'll see that the adjustment is needed to a degree and that they weren't designed for co2 more the big bore pcp's and was a means of getting the efficiency up
on the original the preload was adjusted from the rear as was the distance between the hammer and spring guide
personally think fitting a 2300 valve reducer and a short hammer spring and a power adjuster gets better results on co2