I switched to small diagphrams such as the AKG451 and the AT4041 and 4051 for close micing accoustic. I found that I got a more present and pleasing tone from these mics. Try a small cond. where the neck meets the body pointing in towords the sound hole. Then experimint with trying to find a sweet spot in the room for your NTK. You always have to be aware of the phase relationship between the two mics, but your ears will tell you when you've got it right.