"Groovemaster:" that sounds like a disco cartridge from the Florida incarnation of Stanton, right? (Sorry: I need corroboration because, although I wrote a book about Stanton/Pickering products, I haven't covered them after they went disco because their own product information has been so dodgy and unreliable).
What are the specifications of your original stylus? I know that Jico isn't in the habit of stating certain specs (I disapprove of any needle seller who doesn't give them up-front, by the way).
First, Stanton's products, even in the Florida incarnation, have offered that superb blend between performance and toughness that's always been their specialty. The ruggedness is focused in the stylus assembly. To break a Stanton needle takes a bit of doing. Yet, it can happen. A curious cat can do it. It's unlikely that your original Stanton stylus could "settle in" to the degree that its vertical tracking angle has changed. And I understand that Mr. Bacon likes to personally inspect the Stanton needles.
Imitation needles, however, don't duplicate every feature of the original, even if the patents have expired. They especially don't match Stanton's ruggedness. A dealer once sent me three imitations for my opinion. Two of them were originally good, but their elastomers hardened over time. Thus, five years later, they have the compliance of a wood toothpick and even with increased pressure, they sound awful. Cause: the imitator made a poor choice of rubber for the elastomers.
Stanton's stylus design, although the industry's strongest, isn't engineered with rotational alignment "locking" shapes (The ELAC/Shure's square mounting tube does). Thus, it's possible for a factory final assembler to either get the rotion wrong or to fail to "worry" the rubber elastomer properly so that tension doesn't cause the rubber to settle into an incorrect position. In short, examine your needle, viewing it from the end, and see if the diamond is rotated out of the correct position. If I remember correctly, factory tolerance should be within 5 degrees.
Some imitation needles, especially those that don't track very light or have advanced diamond shapes, can perform well. But they can differ from the orginals, slightly, in vertical tracking angle/stylus rake angle.
So, what I recommend is that you experiment with fore-aft angle of the cartridge. Excessive VTA, even if by only a couple of degrees, can cause the sound to be harsh, especially on the sibilants and other complex waveforms.
I'm interested in knowing if this works for you.