Hi Twintwin,
If all the materials are latex top to bottom then they are all good quality which is the most important part 
I didn’t notice your particular model on their website though (which has latex from top to bottom and no other materials). which of the Comfort Coil or J. Stowe models are you looking at?
My personal preference in terms of durability and “value” would lean towards blended Talalay vs 100% natural Talalay because in the softer ILD’s especially it tends to be more durable and it’s also less costly but of course each person may have different preferences or reasons for choosing one over the other and both would be a good choice IMO. You can read a little more about the difference between them in post #2 here.
You may also be fine with just the 9" basic mattress without the topper in the layering most suitable for your weight and height although of course the topper may be something you prefer. You can read a little more about the potential benefits of a thicker mattress or sleeping system in post #14 here.
There is also a little more information and feedback about the Comfort Coil mattreses in this thread.
Just to clarify as well (not that it makes much difference because the material is the same) … latex International actually makes the latex and Hickory Springs (which makes polyurethane foams) just distributes it.
You are certainly looking at some very nice mattresses that use good quality materials
Phoenix