Hi naiveSkeptic,
It would take a lot more specific information which I don’t have to be able to even guess at a specific solution for you so the best I can do is offer guidelines so that you know how to choose and then you can make a choice based on your actual experience.
I also don’t know the layers that are in the Aster in terms of layer thicknesses and foam density and if you had this information it would also be helpful. The top layers in your mattress will have an effect on how the mattress / topper combination feels and performs for you and knowing what was already in your mattress would provide an indication of how much soft foam is already there.
Natural fibers or feathers will provide some surface softness that is more “point specific” and but they have much less resilience than foam so they don’t really re-distribute weight over the body surface except by “padding” the pressure points. They would have less of an alignment / support risk because of this and because they allow you to go through them into the support layers more evenly they would be less risky for alignment but they don’t provide the same level of pressure relief over the whole surface of the body (they spread weight over a smaller more specific area). They are good if you are looking for more of a surface “feel” and some extra pressure relief on pressure points. Don’t forget that primary support comes from the deeper layers of the mattress not so much the upper layers which are mostly about pressure relief.
The upper layers do provide what I call secondary support though which helps to fill in the gaps in your sleeping profile such as the waist or small of the back which plays a secondary role in helping to maintain neutral spine alignment (the lumbar curve is more controlled by the tilt of the pelvis sinking in to the mattress which is why the support layers that “stop” the heavier parts of the body from sinking in too far are so important).
I would also keep in mind that 24 ILD latex is “soft” not medium (see the Latex International ratings here).
This depends entirely on how deeply your comfort layers (in the mattress and the topper combined) allows your pelvic girdle to sink into the mattress. It also depends on the thickness of the top layers which is just as important as the softness of the layers (thicker layers of soft materials allow your heavier pelvis to sink in more deeply).
I treat “soft” as being in the range of about 19 - 24 and you are on the lighter side so on the lower end of that range would be less risky than if someone was heavier. I would personally be cautious about going softer than the high teens in terms of ILD because the risk of support / alignment issues can be higher (again depending on the combination of the topper and the softer layers that are in your mattress). This would especially be true for stomach sleepers.
In terms of thickness … the guidelines in the link I posted in the last reply (just a touch to a little, a little to a fair bit etc) would be what I would go by.
A good “average” choice if you are undecided would be 2" in the range of 19 to 24 ILD but I’ll stress again the topper will only be part of your comfort layer and what is already in your mattress will be just as important as your topper. I would also bear in mind that the thicker the topper the more it will affect the temperature sensitivity of any memory foam underneath it (making it feel firmer because it will soften less or at least more slowly with a layer above it).
You can find some of the sources or mattress or topper covers in the component / topper thread in the topper post I linked earlier (it’s in post #4 here if you missed it). Local fabric shops that can custom sew and you can choose the material may also be a source.
Rejuvenite is just a trade name for pillows and toppers … it’s not an actual material. Their Rejuvenite toppers use their blended Talalay and have a cover. You could buy blended talalay and add your own equivalent or similar cover and have a topper that was very equivalent.
The Talalay GL has phase change gel in it (and their topper covers use the gel as well) which can make a little bit of difference in temperature until temperatures equalize at which point all foams become an insulating material (even though latex is more breathable than other foams so it will have less effect on temperature than other less breathable foams). Latex for most people sleeps cooler than other foams but if you are particularly prone to temperature issues then the Talalay GL could provide the little extra that you need … particularly when you are first going to sleep. I probably wouldn’t choose it personally because I don’t have heat issues and if I did I would probably use a different mattress protector or sheets to fix it first rather than using latex with phase change gel in it but some people may need every advantage in every layer they can to help with temperature control.
Hope this helps
Phoenix