Hi catalana,
Based on your comments it seems clear that the top layer in the Richmond mattress is a high performance polyfoam which means it would be suitable for your weight range.
The Alexander Signature Hybrid uses 3.5 lb memory foam and 1.8 lb polyfoam in the comfort layers which are both lower density than I would suggest in your weight range.
The Saatva mattress also uses some lower quality/density and less durable materials in the upper layers than I would suggest in your weight range or even lower weight ranges as well.
In other words … I would consider the Richmond to be a more durable choice than either of them for someone in your weight range.
Again I can’t speak to whether any mattress would be suitable for you relative to your weight differences but since you are in the higher weight range if it was durable enough for you then it would certainly be durable enough for your wife as well.
In terms of durability … I would consider any mattress that doesn’t have more than “about an inch or so” of lower quality and less durable materials (in the upper 6" or so of the mattress especially) than the guidelines here to be a suitable choice. Suitable materials for your weight range would include 5 lb or higher memory foam, 2.0 lb or higher polyfoam, any type or blend of latex, or any steel springs.
I don’t make specific recommendations and I don’t keep a record of the individual mattresses or their specs that the retailers and manufacturers in the hundreds of forum lists throughout the forum carry on their floor or have available online (it would be a bigger job than anyone could keep up with in a constantly changing market) but checking their websites and making some preliminary phone calls to the retailers/manufacturers that are on the local or online lists is always a good idea before you decide on which retailers or manufacturers you wish to deal with anyway. This will tell you which of them carry mattresses that would meet your specific criteria, are transparent about the materials in their mattresses, and carry the type of mattresses that you are interested in that are also in the budget range you are comfortable with. Once you have checked their websites and/or talked with the ones that interest you then you will be in a much better position to decide on the ones that you are most interested in considering or visiting based on the results of your preliminary research and conversations.
In other words I can help you evaluate a specific mattress that you are looking at once I know the information in this article but you would need to “find” them by looking through websites or by talking to different retailers or manufacturers that are listed in the local or online lists.
If you are looking for an innerspring mattress instead or an all foam mattress then there are some latex/innerspring hybrids that are listed in post #2 here that would be very suitable choices in terms of durability (latex in general is the most durable of all the foam materials) and I believe if you check their websites or call them for prices that you will find that a few of them may be in your budget range as well.
There may also be some suitable options in your local area as well.
I or some of the more knowledgeable members of the site can help you to narrow down your options, help you focus on better quality/value choices that are available to you either locally or online, help you identify any lower quality materials or weak links in a mattress, act as a fact check, answer many of the specific questions you may have along the way that don’t involve what you will “feel” on a mattress, and help with “how” to choose but only you can decide which specific mattress, manufacturer, or combination of materials is “best for you” regardless of the name of the manufacturer on the label or whether anyone else would have the same criteria or circumstances or would make the same choice.
Phoenix