Alignment of double-line annotation

In ancient manuscripts, sometimes the main body was closely connected with the annotation. The main body is written in big characters, while the annotation is in double-line small characters. To make sure the overall appearance neat, the first line and the second line of the annotation should have roughly the same numbers of characters. Hence it is necessary to calculate the number of characters in every annotation before transcribing them. Otherwise, if the words in the first line are more than the second line, there will be more blanks in the next line; on the contrary, if the number of characters transcribed in the previous line is less, then the words in next line will be too compact or there will be insufficient space left for more words.