Hi Mikes096,
I think the guidelines in post #10 here about memory foam mattresses may help you assess the overstock mattresses you listed.
Almost all of these mattresses include 3 lb memory foam in layers more than an inch thick which for me would exclude them from consideration.
I would also question the ability of the staff at overstock to help you make an appropriate choice for your body type, sleeping positions, and preferences because for them the goal is to sell you a mattress rather than “fit” you to the most suitable choice. IMO … the “value” of the knowledge and experience of the merchant that sells you the mattress is part of a mattress purchase and without this then you are really just rolling the dice in terms of knowing how suitable a mattress may be for your specific needs and preferences. In cases like this … the return policy of the merchant may be the most important factor to consider.
Verlo has some good quality and value mattresses and as further food for thought … some of the better options I’m aware of in Memphis are listed in post #2 here. It may be worth calling some of these to see if they make or sell the types of mattresses you are interested based on your testing and whether they would provide a realistic option for you.
Phoenix