Which Artisan Zip and Link mattress for solid wood bed?

Please can you advise? We would like to purchase a mattress from your Artisan zip and link range. We have a king size wooden bed with solid slats. We both suffer from bad backs. My husband prefers a firm mattress for his back but our current mattress is too firm for me and increases my back and neck pain. Our current mattress is classed as very firm and to me it feels little better than lying on the floor. He has restless leg syndrome and spends all night kicking and moving his legs, I am a very light sleeper. Therefore with so many differences we are very interested in purchasing a zip and link mattress with tailored tension. My husband is 6ft tall and weighs approximately 12 stones. I am 5ft 3" tall and weigh 10 and a half stones. There is not much difference in our weight but we can never agree on the right tension when trying to buy a suitable mattress. What tension of mattress would you recommend for each of us, with consideration also to the solid wooden base it will be resting on? Thank you.