this are my configs on cgminer, with a 7950 saphire vaporX, use them as your own risk cause i had a lot of OC here, also getting 600 kh/s with these settings mining ltc
cgminer --scrypt -o stratum+tcp://stratum.give-me-ltc.com:3333 -u **** -p *** -Q 0 -s 60 -E 120 -I 20 --thread-concurrency 24000 --shaders 1792 --worksize 256 --lookup-gap 2 --no-submit-stale -v 1 --gpu-fan 65-75 --auto-fan --temp-target 75 --auto-gpu --gpu-engine 1050 --gpu-memclock 1475 -g 1