Hi a2b,
As a category, latex is the most breathable and ventilating of all the foam materials (latex, memory foam, polyfoam are the main types) which means that it helps with humidity control in the mattress and tends to help those who sleep hot on other types of foam. It contributes to the sleeping microclimate in terms of humidity and temperature control but since all foams are insulating materials to some degree it would not sleep “cold”. It’s usually described as sleeping cooler because many people have issues with sleeping hot … especially on less breathable materials like some types of memory foam, but it would probably be fairer to say it is the most temperature neutral of the foam materials.
Wool is a more extreme example of this because it is used in cold climates as an insulator (for warmth because of its ability to trap air which is an insulator) and in warm climates such as the desert (in thinner layers) because of it’s ability to store moisture away from the skin and encourage gradual release of the moisture to the environment and regulate body temperature.
You’ve probably seen this but some of the better options in the Minneapolis area are listed in post #2 here. There are some good quality/value choices in the area including latex mattresses but it seems that these are not so close to you.
If you are near Grand Rapids or Duluth then post #2 here may have some possibilities.
If you are in another city or area … if you let me know where I’d be happy to look and see if there are any possibilities in the area that show up with some searching but as you mention you may be best served with an online purchase. It would probably be helpful though if there was something you could test locally if possible (at any price) to get some sense of the “feel” of latex.
In any case … post #21 here includes the members of this site that specialize in online (or better yet on the phone) sales which of course includes SleepEz.
There are some general guidelines relating to body weight here and different sleeping positions here along with how different types of constructions and layering can affect your choices here but these are more helpful to get a sense of how different layering choices work in general and because of the many variations of materials, components, layering, and design that can be used by each manufacturer and because they know more about the specifics of their own mattresses than anyone else … it’s much better and more effective to work with them directly to decide on which of the options each one offers that may work best for your individual needs and preferences. They are the “experts” about their own mattresses and choosing between the different options that they offer.
As long as there is center support to the floor to prevent any sagging in the middle and the slats are supported on a mid beam with gaps of no more than 3" (and preferably less) you should be fine.
You’re very welcome … and I’m looking forward to hearing about what you end up choosing … or of course any questions you may have along the way.
Phoenix