Is it a RV queen mattress? Some online mattress builders say they guarantee their product, money back if not satisfied. here's the catch. You need to donate the mattress and get a receipt and show it to them. Who accepts used mattresses?
After researching a mattress for my trailer I went to a store locally that builds the mattresses, I tested what they had and they made what I wanted. So pleased. Yes it was 700 dollars however, some things I cannot go cheap on and sleep is one of them.
With all the requirements you have, then to cut it up yourself?
Sure, what the Rv builders put in trailers are for kids, not adults. Do a search, there are some good threads on this.