Yarn amounts

I have 9 balls of ribbon yarn. 25g, no yardage shown. The pattern calls for 9, 50g balls. I realize that although the 25g per ball that I have is just 1/2 the g’s they call for, BUT could it be there is still the same yardage because of the “lightness” of the ribbon yarn I have? I hope you can figure out what I am trying to say. OR, could I go to a much larger needle? Please help here. Thanks. Hertha

Have you tried looking up the yarn at yarndex? They might have the yardage listed even if it’s not on the ball band.