With the stock spring try a firmer grip and see if that helps. The spring will break in some but you will break in faster. I would not suggest a weaker spring.
When the HS2000 first arrived I played with reloads to have my then 9 year old daughter shoot it. Heavy loads flung far, light loads came in closer went to dribbling off of my wrists then stove piping at the lightest. Playing with spring weights (custom rod) mimicked the same, too heavy a spring brought on stove piping, light springs flung far out. Grip strength could moderate between these effects.
The stock spring assembly is a dual spring, but there is no first and second stage feel. There is just one spring rate summed with the second spring rate, for an equivalent single spring rate. The advantage of the dual spring assembly is no loose pieces in the dark for military use and a long fatigue life, many having 10K plus rounds with little change in recoil. A single spring setup is cycled deep and will have a shorter life but can get a feel that you may prefer.
I can check again on my dual spring assemblies but my initial scales showed at near 18 lbs, for the stock assembly, using a vice and hanging dead weights of 115gr.bullets until there showed no movement (roughly 1/4 oz resolution).
edited to add: I couldn't remember how good my memory was so I repeated the setup today, but just weighed the hanging mass on a postal scale. 16 lb. 15.8 oz. would fully retract the slide with about 2.6 oz. hysteresis (it would hold in place at a lower weight if moved there, but would not move there on its own). Add the slide weight of 11.5 oz. gives the spring force of 17 lb. 11.3 oz.