[NTG-context] Constraint in line numbers

Hi, this is my first message in this ml ;) Well, I've a stupid constraint in a work: I must limit the number of lines in a page. I have to have 32-35 lines on each page. Now, the task isn't too complex in principle, I can work on interline sizes and glues, but this way is a little bit tricky. I wonder if there is a better (and elegant) way to manage the problem. Thanks Fulvio