Hi reflexbug,
I would make sure you’ve read post #15 here before trying a DIY mattress just to make sure that you have realistic expectations and are comfortable with the trial and error that may be involved in finding a combination of layers that match what you are looking for. I would also read post #9 here about the different ways that one mattress can “match” another.
For reference … to the best of my knowledge the Tempurpedic Cloud Luxe uses the following layers …
Tempur Cloud Luxe (OLD):
Quilt
Stretch Knit Cotton with Suede Sides
FR Sock
Comfort Layers
2.75" 4.1LB Tempur ES Comfort Layer
2" 7.1 LB Tempur HD Support Layer
Support System
Dual Airflow System
4" 2.2 LB Convoluted Base Foam
4" 2.2 LB Convoluted Base Foam
Tempur Cloud Luxe (NEW):
Quilt
Easy Refresh Stretch Knit Cover
Smart Climate System, moisture-wicking,
Cool to the touch
Comfort Layers
3.5" Tempur-ES 4.1 LB
2" Tempur HD 7.1 LB
Support System
Dual Airflow System
4" Airflow Base Layer 2.0 LB
4" Airflow Base Layer 2.0 LB
It’s also possible that the base foam is lower density than these specs indicate (1.5 lbs).
This would give you a reference point but I would also keep in mind that each manufacturer makes their own version of memory foam so one type of memory foam may feel and perform differently from another even if the density and thickness is the same (see post #9 here and post #8 here) so a mattress that had an identical design in terms of foam densities and layer thickness may still feel very different from each other depending on the firmness and other properties of the foams you use.
Some of the better sources for DIY materials and components I’m aware of are listed in post #4 here.
Phoenix