Hi shangkan,
Thanks for taking the time to share your initial comments and feedback … I appreciate it 
It’s certainly easier to do with two people but even with one … once you get the hang of “waving” the layers into place it’s relatively simple. Folding the cover back over the foundation can also help with aligning the bottom layer (see post #12 here).
[quote]The initial feel is quite some firmer than what I felt at the showroom. I am not sure if it’s the tightness of the cover or just variance within each firmness category. I can feel the pressure while sleeping on the side. My wife feels firmer too, but not as much as I do on my side.
I am thinking of doing some changes. Either change the soft top layer to a softer one, if they have. Or change the core from firm+medium to medium+medium. The second choice would be only for my side though. Before that, I would probably give it another week. [/quote]
As you probably know from your reading here there will be a break in and adjustment period with any new mattress and I would probably wait a minimum of a couple of weeks (preferably longer) before making any changes to your mattress to give the mattress a chance to break in a little and for your body to adjust to a sleeping surface that is different from what it’s used to (see post #3 here and post #2 here).
Some types of mattress protectors or mattress pads can also affect the firmness or “feel” of the mattress as well.
Phoenix