Hi malibujason,
I think you’ve answered your own question :). For a latex mattress I would suggest slats that are no more than 3" apart (and less would be better).
There is more information about foundations and other support systems that would generally be most suitable for different types of mattresses and some good sources for each of them in the foundation post here.
Congratulations on your new mattress as well 
I think you made a great quality/value choice and I’m looking forward to any comments or feedback you have the chance to share when you receive it.
Phoenix