168 waves...
Build large ship with tons of guns (40 Gatling turrets, all on one side), place wielder block next to each turret so it will fix itself. Place decoy (or 2), cover them with one layer of heavy armor blocks, use wielder blocks here too. Pack some ammo (I have had 21k but 10k should be enough), tons of spare parts, to feed your wielders (steel plates 10k?, grids 4k? and stuff to fix turrets). Go to the green marker (<100m) to start the first wave. Face your guns toward new spawned enemies and strafe (3-5m/s) to avoid debris. Set your gatlings range to at least 750m and allow them to shoot down rockets. Cover the beacon with armor block and fix it between waves. The Achievement should pop during 168 wave.