Choice of mattress

I am 71 years old with a weight of 13 stone and my wife is a little younger and has a weight of 10 stone. We have used a Maestro 3000 mattress ( super king size zip & Link made by the pocket spring bed company - now defunct) for the last 8 years. We both got firm mattresses and while my wife finds hers comfortable as it eases her neck problems, I find it uncomfortable because of my wide shoulders. I telephoned yesterday to discuss the matter with your friendly specialists, and was steered from the Artisan luxury towards the Artisan Bespoke 004 ( both medium tension) as it would be firmer for my wife. Our budget would also reach the Artisan Bespoke 002, would this give a better chance for my shoulders to sink into the mattress? Should we also consider a mattress topper - my wife overheats with any latex, and I see you recommended a microfibre topper from 'Soak & Sleep' to one of your customers. Can you give me a steer on how to what you think would be the best combination please. Our existing divan base is in good condition so we would probably re-use it.