JonFields method gave me fantastic results. I couldn't find any acoustic IR that sounded good with my Taylor 314ce / Baggs Anthem setup. I followed his instruction to create my own IR and the results were phenomenal!
I adjusted my Baggs so that only the saddle pickup was running without the body mic. I used a Shure KSM-137 and pointed it at the 15th fret and roughly 8 inches away. I plugged the guitar and mic into a Motu M4 interface and then recorded about 70 seconds of strumming and fingerpicking to my DAW, then panned the channels before exporting the audio.
I took the standard jf45ir, imported it to my Helix's IR bank. (I haven't tried any of the other jf45irs yet) I created a preset by adding an LA Studio Compressor, the IR, a 10-band EQ and Stereo Plate Reverb. I can't believe how good it sound.