Hi Clay,
You “loved” it because it was a good match for you in terms of PPP. Of course the ideal is that a mattress is a not only a good match for you but uses high quality, durable materials as well so that the mattress continues to feel and perform close to the way it did when it was new and has a useful lifetime that justifies the price you paid for the mattress. Both low and high quality materials can feel the same when they are relatively new but lower quality materials don’t maintain the way they feel and perform for nearly as long which is why it’s an important part of a mattress purchase to make sure you know the quality/density of all the layers and components in a mattress as part of the purchase process (which aren’t included in the mattress specs you listed).
There is actually more layers in this mattress than you listed. You can see the specs here …
Silk/Wool/Poly
1." 5lb Memory Foam
.5 oz Polyester Fiber
1" Reg Poly
2" Marvelux HD Foam
1.5" 5 lb Memory Foam
Liquid Injected Foam Edge
Intellicoil Id
The 5 lb memory foam is good quality and the Marvelux is “in the range” of good quality as well although it’s a little on the low side for a one sided mattress (I believe it’s 1.7 lbs) so there is about 1.5" of “suspect” materials (which is in the range that I would normally consider acceptable) and another 2" of foam that is “a little on the low side” (the Marvelux).
The mattress appears to still be breaking in and changing over the first couple of weeks so I would probably wait a little longer until the “feel” has stabilized (perhaps another couple of weeks or until it doesn’t seem to be changing any more) before adding a topper.
I don’t know which topper would be closest to the “feel” you like because there are too many differences between the mattresses, too much missing information, and because feel is very subjective and each person can have a very different perception of the same mattress or mattress/topper combination. Your mattress is very different from the Lisbon and all the layers of a mattress can have an effect on how a topper or mattress/topper combination feels so the same topper may feel very different on different mattresses. The upper layers affect the initial “feel” more than the deeper layers though so since the top layers of the Lisbon were mostly softer polyfoam it would probably be worth trying to “approximate” the feel with a topper that was about 2" of a similar material (which you mentioned was convoluted polyfoam) to experiment with and see how close it comes. While it will probably be lower quality foam … the advantage of a topper like this is that it’s less costly to experiment with and can be easily replaced if your trial and error indicates it doesn’t work well for you or if it softens or breaks down fairly quickly over time. The topper guidelines in post #8 here may also be useful.
Phoenix