I pretty sure that the availability of E seats is the same as Award Seats (N seats) for General Skymiles Members. I verified this on several flights. I am a GM, but I have kids that are general members. So I pull award availabiliy on delta.com as a general member (no status). I then spoke with Delta and the number of E seats available was the same as Skymiles Award seats I was able to pull for the same flights

Net, I think E seats are about as easy to find as general member N seats ... which may be hard or easy depending on the route ..

Happydad