I'll try to make this brief.
Ebonite is the parent company for Hammer, Track, and Columbia300. They all have their own research & development, and use different production lines even though the plant is in Kentucky. Some shared principles of coverstock chemistry are used, but each brand has a specific type of reaction or market strategy.
That being said, there are reports from many that say because of the oil absorbing nature of the covers for Hammer and Ebonite, they have seen ball reaction decrease. Counterarguments say that with proper ball maintenance, you shouldn't have a problem. Cleaning, resurfacing, hot water soaks, and rejuvenators help immensely when done properly.
As for the Black Widow line you have two strong balls and the right idea on how to use them. The Venom will give you better length than the Solid (or "Black" as you called it) and a consistent, strong, and snappier backend than the Solid or Bite. Better when you have slightly shorter oil or second-shift/bowled on lanes.
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Ken