Mattress and Topper for Zip and Link

Hi! Our mattress been nearly 10 years and thinking of changing.
Since it has sagged I feel uncomfortable and have pain on my lower back affecting my wake in the morning. My height is 159cm and weigh 43 kg whereas my husband height is 175cm and weighs over 100kg. With such a difference I am thinking of Super king zip and link. My husband is specially a hot sleeper whereas I am not. Can you suggest/recommend which type of mattress and topper we should chose? Thank you.