Hi kate,
Thanks for the additional information.
I don’t generally make specific suggestions or recommendation because I can’t feel what you feel or see you sleeping on your “sleeping system” although there have been a few cases where a member’s specific feedback does seem to “point to” a choice that would be less risky than another alternative that makes “guessing” a little bit easier.
If your back pain has been significantly reduced I would hesitate to “mess with success” and I would probably sleep on what you have for as long as possible to see whether the break in and adjustment period over the course of a month or so makes any difference (see post #3 here).
If you are willing to take the risk of changing a combination that seems to be working fairly well then given your weight it would be a reasonable “guess” to try a Talalay topper that was just a little bit softer (perhaps an ILD in the high teens) in the same thickness.
Phoenix