Hi Wach,
You can see the specs of the PLB Pamper here and as you can see it uses 2" of 21 ILD blended Talalay latex (which has gel added to it to help with temperature regulation although Talalay latex is already the most breathable of all the foam types … see post #2 here) and a 6" 36 ILD blended Talalay support core. It has an unquilted stretch cover. These are all good quality materials and there are no weak links in its design although it would also be the firmest of the PLB natural lineup (which uses blended Talalay latex).
For a mattress to be a close approximation of the Pamper it would need to use the same type of latex in the same layer thicknesses and the same or very similar ILD with a similar stretch cover.
There is more about the different types of latex in post #6 here and a comparison of the “feel” of Talalay and Dunlop in post #7 here but your own personal experience is the most reliable way to know which one you may prefer.
All of the mattresses you mentioned also use high quality materials and are good value but they are also all different from the Pamper either because they use a different type of latex or have different layer thicknesses, a different cover (quilted), or a different ILD in their layers (or a combination of these).
The Spindle Abscond uses three x 3" layers of 100% natural Dunlop with a cover quilted with polyfoam. You can choose the firmness of each layer. They also have an option for a wool quilted cover.
The Rocky Mountain 9" latex mattress uses a 3 zone 6" support core of 100% natural Dunlop and then a 2" layer of blended Talalay. where you can choose the firmness level. It has a wool quilted cover.
The SleepEz 10000 uses three x 3" layers of blended Talalay where you can choose the firmness of each layer and has a wool blended cover. They may also provide the option of a stretch cover (but it would remove the option to split the top layer).
The Brooklyn Bedding 10" Total latex mattress has a 6" core of either Blended Talalay or 100% natural Dunlop (you can choose the type and firmness) and a 3" layer of blended talalay where you can also choose the firmness level. It has a cover quilted with wool and polyfoam.
Each of these also has different exchange and return policies either for individual layers of for the mattress itself.
All of these would be well worth talking to and could make very good choices in terms of quality and value or even in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) but they would all be different designs from the Pamper (which means they may be more or less suitable for you depending on whether the Pamper is your “ideal” or just the best “match” out of what you tested).
There is a list of the members here that supply latex mattresses online in post #21 here and it may be worth looking through their websites or talking with them on the phone because some of these have all Talalay latex mattresses that have designs and firmness options that would make them closer in design to the Pamper than the ones you mentioned (all of this is assuming the Pamper is really the “best” target for a mattress).
Other than this (a mattress that has the same or very similar design, type of latex, layer thicknesses, ILD, and type of cover), trying to match one mattress to another would involve “translating” one design into another which is more of an art than a science and you would need to talk with a manufacturer or retailer to tell them more about you and what you are looking for as specifically as possible so that they could give you their “best guess” about which of their mattresses would be likely be closest to the mattress that you are using as your “target”
There is more about matching one mattress to another in post #9 here and the posts it links to that would be well worth reading as well.
Phoenix