From what I can understand, I can either use one 4 ohm cab, or two 8 ohm cabs with my head, right? I think what my problem is that my 4x12 is 4ohms, or is this gonna be alright? im totally lost with all this junk

edit: Right, I think I'd better put all the info I know about the amp and cab on here...
head: carlsbro glx 150 solid state
cab: matching
the manual says:
power output (at onset of clip): 150W RMS into 4 ohm
on the back of the head, it says:
minimum total load: 4 ohms
on the back of the cab, it says:
left side above jack - input 200W 4 ohms
left side below jack - left input 100W 8 ohms
right side above jack - input 200W 16 ohms
right side below jack - right input 100W 8 ohms
