Googled to find something to replace my Heavenly Bed that is now about ten years old and stumbled upon your great website! I have two bulging discs in the lower back and after sleeping on some other beds while traveling have come to the realization my bed is a major problem. Both my husband and I are 5'7". He is about 155 lbs. Me 135. He doesn't sleep well in any case so let's pick a bed for me! Teasing! He likes firm, I do as well but need some cushioning. Price point about the same as the Heavenly king.
The price point from 10 years ago?
The problem with bulging discs is, that if allowed to continue on their path, they become herniated. Then, you're talking some real pain.
A firmer mattress will help keep those discs from bulging further. A softer bed will have the opposite affect.
The comfort level at the surface should be "Just Enough" to allow you to sleep deeply...relieving pressure points enough to keep from fragmenting your depth of sleep with a lot of tossing and turning.
You are now at the "tight rope" stage. If those discs herniate, you will no longer have much in the way of options.
I would suggest hitting the stores to try those that you may have not considered...the models that feel somewhat less than "heavenly".
After 10 years of that, you can be assured that it was the mattress that has helped you to this point.
Simmons makes a variety of mattresses and has a "Luxury Firm" model at every level in the line. They don't feel all that much different from one another, so it doesn't matter much which you're trying.
At your sizes, the best buy in their line is a Classic Flatbrook model model with a latex foam topper.