Hi Roadrunner,
The SleepEz site has been updated to show the specs of their 2 9000 models here (natural) and here (organic). There are still some pages that show the 8500 title but the descriptions here also show 2". They are working on updating their website and bringing everything up to date but I know from personal experience that this can be an ongoing project 
The KD (knock down) types of foundations appear to be quite variable in their quality and there have been many reviews that indicate some of them use “inferior” wood from time to time (it seems to be variable) and sometimes the spacing is further apart than they should be (over 4" instead of a maximum of 3" apart). In cases like this it isn’t that difficult to add some slats to the foundation but they don’t all seem to be consistent in their quality.
Some of the better or more reasonable foundation options are listed in post #60 here (which also includes other posts with more options if you follow the links).
Foundations are often a little less than the dimensions of mattresses so that they can fit into the frames that support them so this is “normal”.
Local outlets will sometimes also have some foundations with good value but it’s important to make sure that the slats are close enough together and not just buy “any” foundation that they say is good (for latex they shouldn’t be more than 3" apart and less is better because latex is very flexible and will more easily sink into wider gaps).
Phoenix