I think it would be nice for the PDFs to have a section for regionalisms.
In general the hosts do a good job of pointing out Spanish that is specific to their region, but sometimes I'm simply not sure if something is region specific or not. Having a section that clarifies that would remove any doubt.
Por ejemplo, Carlos and Natie are our Costa Rican experts, so in that section they could identify all Costa Rican specific Spanish that was used, and then offer a more neutral version as well as point out how it might be said in other regions such as Mexico or Spain.