Recording two different takes L/R always sounds way better than any "widener" plugin or "sample delay 30ms" approach.
Just doubletrack the guitars, it doesnt take that much time if you can play the part. Practically just 2x the time.
So if you spend 10-15 minutes tracking Left guitar of a 5 minute song, then maybe you would have to spend 20-30 minutes for both tracks.
You probably have time for that.
If you are so good that you dont even make any mistakes and dont have to re-record anything, you can probably play the song in a single take two times so that would take a total of 10 minutes
Totally agree. The OPs request was about how to audition tones which are double tracked. Personally, I would just focus on getting one good tone then change the second one if necessary by reamping against the original track but they seem to want to audition a double tracked sound and make decisions from that.