Using repeating text fields for this is not a good idea. A portal of related lineItems is a better approach.
You could look the description text into a single text field and define two different calculation fields to display the text with these expressions:
Field 1: Left ( DescriptionField ; 30 )
Field 2: Middle ( DescriptionField ; 31 ; 999 )
Note that unless you use a mono-spaced font such as courier, it's extremely difficult to predict how many characters will fit in your field due to the way each letter is one of many different widths.
Thanks for the help.