I used to play electric 12-string and I always de-tuned slightly to get the "12-string" sound. And who knows whether the strings will go from 3 to 5 cents or 3 to zero cents over time. You have to have an ear for what you are doing, and make little tweaks on the fly to get the sound you want. If you like it 2.15 cents, and you tuned it by ear not having the slightest idea where it would measure on a tuning meter, you may find that it goes one way or the other and you'll just need to adjust it to what you want. Original tunings aren't cast in concrete, so have fun and do it the way you want!