Still an impossible call. Circulated coins which tone are a red flag - toning considered "natural" is rarely found on circulated examples. That said, Franklins seem to tone more easily than some other issues and I'd consider a toned, circulated Franklin before other issues.
Your best bet, if you can't make your equipment provide images of the quality you like, is to register with Heritage Auctions (ha.com). They are the largest numismatic auction house, and registering with them (free, no financial info required) gives you access to their huge archive of past sales with extremely high-resolution imagery. They have over 35,000 Franklins alone.
This is one of the most difficult issues to grade. Professional-quality images are imperative to grade them because the differences between grades are so subtle. So, at this point, better to get you in front of thousands of grading-quality images so you can learn the subtleties of grading these from known-grade examples.