+/- before the Memory Clock value indicates an offset memory clock. If it is simply the number, it indicates a locked memory clock.
Command Line Launch String:
Replace [Wallet] with your wallet address and [Worker] with your worker name
miniZ.exe --url=[Wallet].[Worker]@flux-us-west.minerpool.org:2033 --pass=Password1 --memoffset=-500 --gpuclock=570