A language is a dialect with an army and a navy.
--Max Weinreich

We recognize variations--dialects--of our mother tongue, and whether we like it our not we have gut-level reactions to them. Usually we feel most comfortable with the dialects we heard as children. Others sound exotic at best; at worst, alienating, off-putting, even incomprehensible.

There is considerable variation in the Spanish-speaking world, hence the documents presented here and elsewhere will likely require revision to suit your patrons.

I think the best way to get this done is to rely on native speakers familiar with the Spanish spoken locally, not forgetting to pay your consultants fairly for their labour--er, for their trouble, as we like to say back home.

If that isn't possible, then pay attention to your Spanish-speaking patrons. Ask questions and observe to discover what sounds good and what sounds odd to them. For example, if a certain question on one of your forms generates unexpected responses, you need to revise the wording of that question (regardless of how "correct" the local Spanish teacher says it is).