Coordinate systems for seed files

I am setting up seed files that I want to ensure follow the same coordinate system as our survey. The survey will have a coordinate system and in the past we simply referenced it into the seed and called it happy. If I want to have a seed file with the same coordinate system, do I need to make sure my design units are in survey feet or does that matter once the coordinate system is assigned? Because we do work all across the country I'm hoping to make the seed as versatile as possible.

Thanks