Impossible good Wifi design, but I have to try. Ekahau and galvanized metal material

Afternoon,

I'm redesigning through Ekahau Pro a building for one of our sites. I received the building materials back from construction and to my horror, it's all galvanized steel including metal doors. The building is a dorm building, hallways on the outside (APs are on the roof here), with rooms and doors facing the outside. Think of a motel type design.

This is a big metal box and a shit show for RF. But I have to try. It's a remote site in the middle of the forest and the folks in the dorm building need wifi. currently they have real shit connectivity, no shit it's metal.

Well, they asked me tot try, more APs etc if possible. I'm gong to model this on Ekahau but can't find loss through a galvanized metal wall in terms of dbm.

Anyone have ideas how they would approach this? My direct answer is, this is a lost cause, but I'm forced to try (upper mgmt).

In Ekahau Pro, the best case is I'll use a custom wall type with a high dbm loss rating. Any other ideas?