Using a weight of 280 as a baseline, from a quick perusal of this roster it seems like Williams (283), Black (277), and Harper (292) are the only ones with suitable weight (at this point) to play defensive tackle ...and Black barely making weight at that. I am not including Elmore on this list. Let him stay at fullback.
There are 2 players that might push to make a reasonable defensive tackle weight by fall: Rondi (269), and Okechukwu (268). There's one other player at playing weight, but looks like a walk on (Kevon Darton 287)
This tells me that Black should in no way, shape, or form, be moved to defensive end. He is going to be too valuable as a rotation player with McKinley. Some will probably argue that this is Black's last year and he shouldn't be relegated to the second line, but that means Harper better be ready or Rondi makes another weight jump by fall