Without knowing the mic pre's I would bet that:
The SM-7 on acoustic guitar
The Rode NTK on Vocals
or completely the other way around...
You will need to try both as it also depends on the sound you are looking for. If the singer can belt than you will want the sm-7 in front of his face, if he is more "breathy" and light go with the Rode NTK...
These should be your best bet and give you the most useable trax.
Let us know what worked!
"sic gorgiamus alos subjectatus nunc"