ETABS Auto Wind Analysis -- "Deck" or "Slab"?

[YCLJ]

I am using ETABS Auto Wind with ASCE7-10 for 4" cover on 2" deck composite floor system, with a roof that has a 1.5" roof deck (no slab on roof). Wind load is based on diaphragm extent. I intend to ONLY model the lateral elements (perimeter walls), but NOT the interior steel framing.

Questions:
1. For the slab on deck floor,
With the slab on deck, I am going to assign a "Rigid" diaphragm. To define the extent of the floor, should I use "Deck" section and define the actual 4" on 2" deck section, or should I use "Slab" section with only a 4" slab to count the cover thickness only? I just need it to define the extent of the floor plate, so that my diaphragm dimensions are correct for the Auto Wind calculation. What caught my eyes with "Deck" section is the SPAN direction arrow shown when you assign, which really doesn't matter to the Auto Wind calc. Does it matter at all whether I use "Slab" or "Deck" section?

2. For the roof,
With the 1.5" roof deck, I am going to check its diaphragm deflection to see if it qualifies as "Rigid" diaphragm per IBC, but for now, I assume it is rigid first. Same question as above: Should I use "Deck" section or "Slab" section? In this case, "Deck" makes more sense since there is no slab on top to define it as "Slab" section, but again, it's odd to see the SPAN direction arrow when it actually doesn't matter at all to the Auto Wind calc. Should I use "Deck" or "Slab?

Thanks.