You can use skip adding this categories to hiding list if this categories won’t overlap with your skin model.
For example, if your skin have big helmet, you won’t be able to mix it with tara, earrings, mask, etc, because helmet will overlap or will completely hide them. And that way you will need to add this categories to hiding list. The reasons for that, firstly, techincal optimization for rendering objects in-world (why you should be able to wear earring and increase lags in-game, if earring completely not visible and not compatible with your skin wearable), secondary, to avoid visual issues, glitches, bugs and overlaps with other wearables.
I would like to build a suit and keep the head free. Or can the double number of triangles be used if i built this suit based on the upper and lower body?
That way you should publish wearable as upper_body slot with lower_body listed in hiding list, instead of using Skin category. Your triangle limits will be 3000 that way.
Or, you can even do this: upper_body + lower_body + feet as one upper_body slot. (lower_body and feet in hiding list) That way you will have 4500 triangles limit.
Here is explanation that written in curators documentation
