@Se**
, using single entry visas at some point is gonna come back and bite you one way or another. Either you're gonna get a warning stamp from a consulate from hitting it too many times, or you're gonna get grilled comin' in because of your visa history.
A METV is definitely the way to go. I don't know a single person who's ever been questioned entering on a 6 month METV from ANY border crossing or by air.