Hi Haas,
I think you are very wise to go slowly and take all the steps you can to make sure you end up with the most suitable choice for all your needs and preferences.
The first place I would start (in case you haven’t already read it) is post #1 here which has the information, steps, and guidelines that will help you make the best possible choices.
Second … regardless of whether you end up making an online or local purchase … I would strongly urge you to do some local testing to get a good sense of the types and designs of mattresses that are most suitable for you and your specific criteria. Nothing can replace familiarity with different designs and good local testing in terms of increasing the odds of making the best possible choice.
Some of the better options or possibilities I’m aware of in the Raleigh area are listed in post #6 here and there are many options where it is possible to test different styles of latex mattresses in the area which would be very helpful regardless of where you end up purchasing.
A mattress will be one of the most important purchases you make in the next decade and can have a bigger effect on your overall wellbeing than almost anything else so I would again encourage you again to take your time and of course feel free to ask any questions you may have along the way on the forum.
Hope this helps 
Phoenix