Hi Xenogear74,
Before considering any Beautyrest (with or without a topper) I would read the tutorial post here which has all the basic information, steps, can guidelines you will need to make the best possible choices … and avoid the worst ones.
If you have already purchased the Beautyrest and have no other options available then the topper guidelines and some of the sources that are linked in post #8 here may be helpful.
Post # here has more about the different types of latex. If you prefer the feel of Talalay I would go with blended talalay for the sake of durability and cost and if you prefer the feel of Dunlop then I would tend to go with 100% natural Dunlop. There is more about the difference between them in post #7 here but your own experience and testing is the most reliable way to know which one you prefer.
Phoenix