Another option is to use a fig-8 pattern on the vocal mic with the side aimed at the guitar and allow the almost complete side cancellation to eliminate the guitar leakage into the vocal track.
How would you aim the side of a vocal mic at the guitar? Are you singing to your feet? or to your crotch? lol =D
Ive always found Acoustic guitar and vocals work best in a nice Warm, almost live sounding room, Cond mic from both guitar and vocals, guitar on Omni, catching some of the rooms dynamics, and vocals nice and close. This being so you can add reverb or echo, whatever afterwords. This seems to give me the best sound that truly "sounds" live like your really their!
"Who says you need a guitar" - Jack White
Think about it, turn the vocal mic 90 degrees.
I've had great success when recording acoustic guitar and vocals using 2 mics setting about "neck high" to the singer and 18 inches away on a stereo bar. I have used matched pairs and 2 different mics all with great results. The vocals are clear and upfront and the guitar sounds huge. If you use 2 different mics, you can hear the tone change more on the guitar than the vocal. The vocal stays tight in the center but sounds great.