I have seen reference that the Brazilian Navy dropped marker buoys very early in search, so some real surface drift should be known.
The expected currents were in this post, which partly explains the search area
mm43's post
But your suggestion is remarkably similar to that suggested a long time ago - do check the date posted
takata's post
I wonder if it is now possible to map where the wreckage is not - the original visual search will have oveflown the expected flight path etc...