Hi Pilou, it doesn't really matter which particular unit system you use - the unit system is just a label.

It matters more whether you use particularly large or small number values, like if you have coordinates like 10000000000.0 or stuff like 0.000000001 units - you don't want to have very large or very small numeric values like that.

But if it helps you to avoid using smaller or larger numbers to use a particular unit system then by all means do that.

- Michael