If I were doing it, I'd leave it on the table after the first side was milled.
Then I'd build a dam around the piece and replace all the removed material with fixturing metal (like Cerro-Tru); finally facing it off flat on top.
THEN I'd flip it over, and not need holding tabs or any of that.
For extra holding power, tap gently to remove the fixturing piece and glue it back on with thin cyanoacrylate... BTDT... that holds better than the natural surface adhesion of the Cerro-Tru, and is easily removed with acetone after remelting the Cerro-Tru.
Holding tabs would just mess up the look of that whole piece, and require a lot of manual 'touch' to get them cleaned up. The Cerro-Tru is re-usable, so after the first purchase, it costs almost nothing.
LLoyd