Hi Jgigs.
Welcome to our Mattress Forum :)!
Congratulations on your mattress shopping journey thus far! You seem to be heading in the right direction.
I am glad that the forum has been offering you valuable insights. Yes, I think you are heading in a good direction with an all latex construction. The first thing you already accomplished was to determine if you like the mattress feel.
It’s likely that this mild back pain you’re experiencing can be attributed to your mattress. Lower back pains (especially in the morning) can be often an indication of foam breakdown and mattress sag compromising a neutral spinal alignment. I imagine you’ve come across this resource already, but if not, you may be interested in reading more about sleeping positions.
The feel of latex can sometimes require an adjustment period if you transition from memory foam products. Latex has the ability to be soft and conforming when it is initially compressed and then become firmer more quickly than other materials when it is compressed more deeply by someone of a higher BMI and “pointier” body shape. You probably know this but it’s worth mentioning that Dunlop Latex has a different “feel” and performance than Talalay Latex and is less lively or springy. You can see a comparison between Dunlop and Talalay in post #7 Your own experience is really the only way to know which one you prefer with any certainty.
Both configurations you mentioned would be suitable for your BMI and sleeping position. I would make sure to buy a mattress from a manufacturer that allows for layer exchanges; then you really can’t go wrong. You’re correct that you could swap the firm and medium Dunlop layers, for a firmer feel. Or, you could always ask the manufacturer to exchange a layer for you to help get you to the firmness that you are looking for. That’s one of the great things about being able to configure latex!
I hope this helps ease your mind as you move forward with your new latex mattress!
Please keep us posted here on how things turn out.
Phoenix