Hi MJ73,
I think that the links in my reply in post #11 of your other thread here would be the same ones I would include in this post as well.
As you’ve mentioned … arms falling asleep generally indicates a comfort layer that needs to be softer or thicker. The next most common reason is probably a pillow issue (likely needing a thicker or firmer pillow) which could also affect pressure on the shoulders. I would also check some of the other possibilities mentioned in the other reply (such as your mattress protector, any mattress pad you are using, or even sometimes sheets). Of course the initial break in or adjustment period is also a possibility but this would generally lead to gradual improvement over time … particularly if you walked on the mattress to speed it up.
Like every other material … the layers can be softer or firmer or thicker or thinner and designed and layered in different ways so this is not generally an issue of the materials as much as it is your comfort choice or the suitability of the design for your needs and preferences. It may indicate the need for a topper as well and post #2 here can also provide some guidelines with this as well. I would first talk with Mattresses.net as well for any suggestions and to confirm the ILD of your base layer.
If it is 36 ILD … then a 3" 24 ILD latex layer under the 3" of 19 ILD would give you a very similar overall design to the Beautiful with the only real difference being the wool quilting and the cover.
Phoenix