Looking for a little guidance before I make decking choices.

I'm in the process of developing screened porch/deck plans for my home. The enclosed screened area will be rougly 20'x 15' (20' along the house). I would like to use some type of T&G plank (Ipe, TT Floorizon, PT, etc.) but am concerned about the moisture buildup beneath the deck resulting in mold and cupping. At the base of the house the deck planks would be ~12-14" above the ground and sloping away from the house to ~36" at the front of the deck. Only two sides (front and one side) would be exposed to air, as the other remaining side is part of a retaining wall. This porch would be built in Northern Virginia.

Is this type of environment suitable for a T&G application as is, or do additional steps need to be taken to avoid potential moisture buildup? Is one type of material going to reduce the issue of mold buildup vs another (I assume using a PVC product can reduce the cupping issue)? Or do you say don't go the T&G route?

Would a better alternative be to use conventional decking planks with the manufacturer recommended spacing and screen the underside? I assume this would give me the neccessary ventilation between the planks.

Any thoughts and previous experience would be greatly appreciated.

Thanks!