Hi Shipmeister,
The first place to start your research is the tutorial post here which includes all the basic information, steps, and guidelines that you will need to make the best possible choices … and avoid the worst ones.
As you will see each person is unique in their needs and preferences so the tutorial will help you with how to choose rather than what to choose. Your own personal testing or experience is the only way to know which mattress is best for you because nobody else can feel what you feel on a mattress.
If a mattress is being sold without a warranty I would be very cautious because it’s likely to be a factory defect or a used or returned mattress.
The Renewal Refined is a memory foam mattress … not a latex mattress. You can see the details of the design in post #1 here.
I would be very cautious with this mattress at your weight both because of the thickness and softness of the comfort layers and because it has 2.75" of 4 lb gel foam and because of the inch of low density polyfoam that it also includes in the upper layers. If you do decide on memory foam I would focus on memory foam in the 5 lb range or higher. Outside of the fact that it’s not particularly good value this could be a risky purchase for you IMO and at the very least I would make sure that you do some very careful and objective testing on the mattress to confirm that you have good alignment in all your sleeping positions.
Some of the better options and possibilities I’m aware of in the Sacramento area are listed in post #5 here. No matter where you buy though I would make absolutely sure that you know the details of every layer in a mattress because it will be especially important for you to make sure that there are no weak links or lower quality/density materials in your mattress.
Phoenix