Hi Boiler65,
You’ve most likely read it already if you’ve been reading the forum for a while since so many posts refer to it but just in case you haven’t the best place to start is the mattress tutorial here which has most of the basic information, steps, and guidelines and answers most of the questions that most people will generally need to make the best possible choices.
With your higher weight there are certainly some additional risks and considerations that would be involved in a mattress choice and post #3 here and the posts it links to has more information that will be helpful for those that are in a higher weight range. The process and steps involved in choosing a mattress would be the same as for anyone else in any weight range with the exception that in higher weight ranges it’s always a good idea to focus more on more durable and long lasting materials and to be aware that firmer materials will generally feel softer to you than they would for someone that was lighter because you will compress them more.
One last “general” suggestion would be to make sure you deal with knowledgeable and experienced manufacturers or retailers that are familiar with the needs and challenges of their larger customers so that the advice and guidance you get from them is based more on “helping and educating” you than just on “selling you” any mattress they can that may work well for someone else but may not work as well for you or won’t last nearly as long as it would for lighter weight ranges. In many cases the knowledge and experience of the manufacturer or retailer you are dealing with can be one of the most important parts of a successful mattress purchase … especially when your circumstances are more challenging.
If you let me know your city or zip code I’d also be happy to let you know about any of the better options or possibilities I’m aware of in your area.
Phoenix