The dakka fex (elite fex) is 2 TL devourers and Enhanced senses. The Gunfex's are usually VC, BS, ES, EC and reinforced chitin for 188pts. Since u want to make a 1K list, you can't fex's as elites, so i'd fill the elites with shooty warriors. Troops i'd take gaunts with flesborers, some with devourers and maybe some with spinefists if u have the points. HQ would be two Tyrants (or one when restricted by points). Thhese can either be walking, or equip one with wings, 2 TL devouers, ES, Warp shield and TS. It can pump out a lot of shots and be monouverable (yeha i know i can't spell). If it's a walking tyrant then a couple of guards could be effective for the extra wounds.
It all depends on points you're playing, so some things you might not be able to take. Write up a list or somehting and post it in the armlist section and we'll be able to critique and give some more specific advice. Happy hunting