Limit on size of lines= variables
The limit on the size of lines= variable is based on the number of characters in the variable, not the number of lines.
New line characters are included in the character count, so that you can get more text into a lines= statement written using long lines versus one written using short lines.
The limit is about 2000 characters per lines= variable, including carriage returns. It does not seem to make any difference if the text is defined inside of a tabset or not, nor do maxv or s size, core, or stack sizes make any difference.