Hi ellemas,
It’s great to see that you’ve already read the tutorial post (a large number of people who post on the forum haven’t read it first :)) so you already have a good idea of the steps involved in making the best possible choice … and have some idea of what to avoid and why.
The better options and possibilities I’m aware of in the Hamilton area are included in post #8 here.
I would also do as much of the preliminary work and research as possible on the phone before you visit them so that you have a good idea of what they have on their floor and the types of mattresses that you may wish to spend time testing before you take the time to visit them.
Phoenix