Hi keyatt,
Savvy Rest uses Radium for their Talalay supplier not Latex international and this is also SleepEZ’s “default” Talalay latex supplier although they have blended and 100% natural Talalay available while Savvy Rest only has the 100% natural Talalay. There is more about the different types and blends of latex in post #6 here that can help you make more “apples to apples” comparisons between different types of latex that different manufacturers use in their mattress but 100% natural Dunlop latex made by different manufacturers would all be closely comparable in terms of quality and durability and Talalay made by Radium and Latex International would also be closely comparable as well if they are the same blend (100% natural vs blended).
The warranty of a mattress isn’t particularly important because it only covers defects and defects in materials will tend to show up early in the life of a mattress (the first year or two). Warranties aren’t an indication of how long a mattress will last for you and don’t cover the gradual loss of comfort and support over time which is the reason that most people will end up replacing their mattress. There is more about warranties in post #174 here but the quality and durability of the materials in a mattress are much more important than the length of a warranty.
When you can’t test a mattress in person before you buy it then the most effective way to choose which design or layering options would be best for you would be based on a more detailed conversation with an online retailer or manufacturer that can “talk you through” the options they have available that would have the best chance of success for your body type and sleeping positions based on the"averages" of their customers that are similar to you (see mattress firmness/comfort levels in post #2 here) or that was a close approximation to another mattress you have tested locally that has a similar design and materials. The tutorial post also includes a link to a list of the members here that sell their mattresses online (in the optional online step) and several of them make component latex mattresses that have a very similar design to Savvy Rest and also use various combinations of 3" latex layers with a choice between different types and blends of latex in different firmness levels. There are also others that have different component designs that also have replaceable layers that may also be worth including in your research. Most of them would be familiar with the Savvy Rest mattresses and how their layers and firmness ratings compared to Savvy Rest as well so they would be the best source of guidance about which of the options they have available would be closest to a Savvy Rest that you tried and preferred.
There is more about the types of foundations or support systems that are generally suitable for different types of mattresses in the foundation post here but for an all latex mattress I would make sure that the gaps between the slats were 3" or less which would rule out many KD foundations. The SleepEZ foundation would certainly be a suitable choice. I don’t know the specifics of the metal bedframe you have but there is more about choosing a suitable metal bedframe in post #10 here.
Phoenix