I just wanted to post an update.
With Chuck’s help I chose the #7 and although I agree that it is better to error to the side of firmer, I think I could have gone with an 8 and it still would have been plenty firm. I now have to add another layer of softness since I feel pressure on my hip and shoulder. I really tossed and turned last night.
I did try the 3" topper that I bought for the other bed and that resulted in lower back pain since my hips sink a little too much. I decided to try the Seven Comforts topper offered on Amazon and will report back once it arrives and I have a chance to use it.
Also, the 3" topper seems to be a good choice for the Natural Response, although I have yet to spend a full night on it. There is no telegraphing of the dip. My problem now is to find sheets with deep enough pockets since the mattress is now a little over 16" and I don’t want to suppress the topper too much.
BTW, I received a free pillow with my purchase because I told Chuck that I am a member of this fabulous forum. I am happy to report that my life long search for the perfect pillow has ended. This pillow can be firm or soft, flat or high and stays put with no “framing” needed from my arms. I want more and would like to give them as gifts this holiday. I’m seriously considering buying latex scraps and making the pillows myself.