Is there any particular aspect I should be worried about if I go the Natura way? Any advice would be appreciated. I tried posting before, but have gotten no responses. Although the Natura I'm looking at isn't  as expensive as SavvyRest (and not completely organic either), it is quite an investment and I would appreciate any comments.

there are many variables here so it's hard to advise. I would say buy the one with all latex. we had the one with memory foam on top but it was too soft for us as the foam was 3". I found the all latex very firm, and so a topper of something like softer latex or memory foam of no more than 2" would likely do the trick.

Thanks so much for your reply. Can you advice on what kind of topper you would buy? E.G. Costco vs. one of the more luxury brands? Would it make a difference?

i really like the memory foam topper that is 2" thick and 4ild from Healthy Foundations.com

I believe that there is also now available 5 or higher ild memory foam toppers - not sure where, you'll have to search the internet.