Hi Tahoegirl,
There is no way for me to know this because there are too many unknowns, variables, and personal preferences involved but post #2 here and the topper guidelines it links to has more information that can help you use your sleeping experience as a reference point and guideline to help you choose a topper that has the best chance of success. In the same ILD … Talalay will be a little more resilient than Dunlop (there is more about the difference between them in post #7 here). For most people a 2" topper in a reasonable firmness level for their body type would provide somewhere between “a little to a fair bit” of additional softness and pressure relief to your mattress but your own sleeping experience will be the only way to know with any certainty whether a mattress/topper combination is a good match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences).
Phoenix