Hi paladin72,
There are really only 3 ways to duplicate or at least “approximate” another mattress that you can read about in post #4 here and the link it includes as well. Every layer and component will affect the feel and performance of every other layer and component and each difference between them in components or materials, layer thickness, layer ILD, type of layer (convoluted vs solid for example), design, and type of latex (natural vs blended) and the cover and quilting can make a difference. Different people will also be more or less sensitive to the differences and some people may say that two mattresses feel “exactly” the same while others may swear that the same two mattresses feel completely different. It will also depend on body types, sleeping style, individual preferences and sensitivities to different changes.
Overall though and for most people (but not all) the layers closer to the middle and top will have a more obvious affect how a mattress feels and performs than the layers closer to the bottom.
Since you are not able to test each mattress side to side in real time to see how close they may feel for you (which would be the most accurate way to know) and Brooklyn Bedding hasn’t designed it’s mattress to be a replica of the OMI … you would be dependent on trying to approximate the design and specs of the Terra.
The first step doing this would be to find the details of the mattress you are trying to approximate. This would mean knowing the type of latex, the thickness of the layers, and the softness rating of each layer and then doing your best to try and “translate” it into another design that would hopefully be close enough that you could fine tune it based on your own personal experience.
So since you can’t do side by side testing and the mattress you are considering (or the others that are available to you in post #21 here) don’t have the same design as the Terra either … step 1 would be to confirm the specs of the Terra that you tested (it can comes in different versions). Post #6 here may also be helpful but again I would confirm that that is what you tested.
Once you have done this then you would need to 'translate" one design and try to “fit” it into another (with the emphasis on the upper half of the mattress) using educated intuition or guesswork to get as close as possible.
Phoenix