Replacing a ikea sultan mattress and sultan topper

hello, I am considering a latex mattress as I sleep on my front and have a difficult time getting a good nights sleep at home. I visited Germany for a fortnight last year and slept on a hotel foam mattress which was the best sleep I had, had, in years.
I have a sultan base, mattress and topper from ikea at the moment and i'm considering replacing the mattress with a latex model (fusion 5) I am 14 stone and my partner is 8.5 stone. we have always thought the sultan was too firm hence the topper aswell. any advice would be appreciated in the choice of a mattress.
kind regards
steve