That's why I used Singer color coded needles for so many years. I now have a small loupe or magnifying glass to read Schmetz sizes.
A QBer named Ripstitcher made a needle case for machine needles that was charted for different sizes.
http://www.quiltingboard.com/main-f1...ml#post6945927
She has the pattern on her website
http://bionicgearbag.com/coming-soon/