Hi tonyandheather,
The first place to start is the tutorial post here which has all the basic informtion, steps, and guidelines you will need to make the best possible choices and includes links that will answer most of your questions.
There are too many unknowns, variables, and personal preferences involved for anyone to make specific mattress suggestions based on “theory at a distance” (see mattress firmness/comfort levels in post #2 here) and only your own testing or personal experience can know which mattress is best for you in terms of PPP. The tutorial post also includes a link to a list of several of the better online sources I’m aware of for manufacturers and retailers that use tempurpedic as a reference point and that are a reasonable approximation for their mattresses. if you are more comfortable with a local source then your own testing and comparison will tell you which mattress comes closest to the Allura based on how they feel to you.
When you get to step 3 … if you let me know your city or zip I’d be happy to let you know of any of the better options I’m aware of in your area.
Phoenix