How Low To Bring Metal Siding & Foundation Protection – GreenBuildingAdvisor

Our home design has our final grade 12″ below the top of the stem wall. The joint between the exterior foam covering the stem wall and sheathing are air sealed via Fentrim 430 Tape. Our siding will be 7/8″ corrugated metal hung vertically over a coravent rainscreen. My question is, should we keep the siding a certain measurement from the final grade for splash protection and also to make sure airflow for coravent is unimpeded and it doesn’t pull overly hot or humid air from the ground behind the siding? Our sider said he can take the siding to the ground (we do like the look of a smaller foundation reveal),  but I’m thinking it should be off at least 6″ or so? Or should we keep the siding off the ground nearly the full 12″? 

Our second issue then is what to use to cover the exterior foam. We’ve read a lot of articles on this site and it’s looking like our only real options are metal flashing or a product like Insul-Guard. Other options would be too thick, require warmer weather or Adhesives which likely wouldn’t stick well due to how long our former contractor left the foam exposed. Does anyone have good reviews for either? The concern with metal would be oil canning and the concern with a product like insul-guard would be waviness.