Choosing a mattress

I weigh 7.8 stone and my wife weighs 9.5-10.5 stone so we need a mattress which is soft on one side and firm on the other. Having read your replies to faq's we would like calico pocket springs so our choice is narrowed to the Artisan Bespoke or Luxury mattresses. Because we are side/back sleepers, you said to be sure to choose a mattress which was not too firm in the upper layers. Is the Bespoke 004 not too firm in the upper layers or would it be suitable for us? If it would be suitable, what would we notice if we bought a Luxury, Bespoke or bespoke 002