Hi Canabuc,
Unfortunately you are in a tough position because none of your options are particularly good ones if you need to exchange for another mattress in the same store. Post #2 here has some links to other posts and replies to members that were in a similar position and has some suggestions about how to make the best of a rather difficult situation.
You at least are on the right track which is to minimize the use of lower quality foam layers in the upper parts of the mattress … even if that means purchasing a much firmer mattress … and then adding your own comfort layer in the form of a topper.
Unfortunately the Ansleigh Black has over 4.5" of unknown or lower quality foam in the upper layers and this could also be an issue over time with foam softening.
I would personally go firmer and reduce the unknown and lower quality foam even more and then make up the difference with a better topper. At the very least I would want to know the density of the memory foam in the Ansleigh. If it was at least 4 lbs then I may reluctantly consider it if you were under 200 lbs.
While they are also not particularly good value … it may also be worth considering some of the Serta iSeries because some of them use some better quality foam and less “junk foam” in the comfort layers and in this case you may not need a topper.
There are also many smaller factory direct manufacturers in the Montreal area (see post #276 here) and many of these would likely sell toppers that have good quality and value. I know that Literie Laurie sells latex toppers (and supplies the Talalay latex topper that Costco sells). This thread may also be of interest.
[quote]My thought process is to try it as is but to have a low threshold to order a 2 inch blended Talalay Topper from AMC.
They now ship to Canada and seem to be reasonably priced for the quality.
was wondering if I need to order the bamboo topper cover and how good it fits since it is made to go over a 2 or 3 inch topper.
Also wondering if there is a discount for members here, as the shipping costs are about 20% of the cost of the mattress and I may still get hit with duties and taxes.[/quote]
It would probably be better to call and ask them about the cover for the topper because I’m not familiar with it and they would be more familiar with their own products than I am. You would definitely need a cover for a latex topper to protect it from ozone and ultraviolet light and other factors that could cause the latex to degrade more quickly than it should. There shouldn’t be any duties although there may be some brokerage fees and taxes. The discount for forum members is for mattresses only but it never hurts to ask 
Phoenix