Between the two you would want the DL8s. Missile Racks have half the damage radius of DLs both before and after pilot radius implants. They also unload all at once while you can pick your shots with the DLs and with the big splash radius, bounce your shots off the walls, floors and ceilings for double damage from behind.
But except for the Shotguns, no 8EN weapon is really good for endgame in Tournament. So you want to figure out your resources carefully not to over invest in them. The DL8s aren't a must-get weapon, but the 12 and 16s definitely are. However they can combine up with those to make 20/24EN combos which is especially useful before you get your 12/16s up to Rank 6 and have 2 copies of each.