I have a few questions regarding the interaction between Mithril and Armored Kilts in Pathfinder. I would like either official sources, or the words of pathfinder creators/developers if possible. I'm hoping to find good rules basis to convince my GM that a mithral chain shirt with a kilt will wind up still being light, but I'll accept if the rules or developer commentary states otherwise.
My thoughts below come from the fact that if medium and heavy armor is made with Mithril (e.g. a Mithril Breastplate), it is considered 1 armor category less than what they usually are. This affects properties such as movement speed.
Adding an Armored Kilt to armor, on the other hand, raises the armor category by 1.
So let's say you have a simple chain shirt. If you put a kilt on it, it counts as medium armor.
Now if that is a mithril kilt, would it still make the chain shirt count as medium armor in terms of movement speed reduction? And if yes why?
Alternatively if you put a normal kilt on a mithril chain shirt, would it still become medium armor in terms of movement speed reduction?
And lastly if you put mithril kilt on a mithril chain shirt would you still get medium armor's movement speed reduction?
I would like to add that the armored kilt table itself does not mention or specify any movement reduction. So for me there is the chance that the armored kilt might not even make the armor slower even if it increases it's category by 1.
Please do not answer simply with the train of thought that it goes:
Chain Shirt (light) -> Mythril Chain Shirt (Still light) -> Kilt makes light into medium.
I am looking for an answer with quotes from rules and developers.