Hi Everready073,
As you probably know the Entice has 3" of Active Fusion slow response Talalay latex over 2" of Talalay latex over their 8" bonded core which is 10% latex and 90% polyfoam (see post #6 here). I don’t know the ILD of the layers (the active fusion slow response would be either 15 ILD or 21 ILD) but PLB would probably tell you if you are able to connect with them. The entice is a soft mattress and I believe is an 8 on their “plushness scale” not a 1 which they say on their site but is clearly a misprint. I believe that the Vitality (in their hybrid fast response line) and the Nutrition (in their natural Talalay line) are both listed as an 8 as well so you can use them as a reference although they both use fast response Talalay in the top layers.
The Active Fusion Slow Response topper is the same material and is 15 ILD so if the topper you tried was 3" then you would have a reasonable reference point once you are able to find out the ILD of the top 3" of the Entice although the layers underneath would also have an effect on how the combination feels so the comparison with the 3" topper on what was likely the Harmony (which has 3" of Active Fusion fast response Talalay over the bonded foam core) won’t be exact.
Hopefully you will be able to connect with PLB and find out the ILD’s but you could test the other 8’s to at least get some sense of the relative firmness level.
Phoenix