Thank you for this, I was able to do the Export / Import and it worked perfectly.
My follow up question is what will happen if I try and import over and existing set of Custom Post Types and Custom Fields? Lets say I want to exand what I've already done, so I do that on a staging environment not moving anything, but just adding new tabs and new custom fields to existing tabs and the new one. Then I export the NEW JSON and them go to import on exisiting sites, will it mess with the data that has already been imput into the exisiting custom fields? Does this make sence?
Also.. on a side note - where in the DB is the custom field data stored