If i want to apply this

 -mt <n> VRAM timings (AMD under Windows only): 0 - default VBIOS values; 1 - faster timings; 2 - fastest timings.
     The default is 0. This is useful for mining with AMD cards without modding the VBIOS. If you have modded BIOS,
     it is probably faster than even -mt 2

To only one GPU of the 6 that has got the rig, how i can do it?