Casper,
I know there is a bit in Nova-T that you can change the default contents of the timetable cell and I think the font size. But if NOVA-T isn't liking this then the quickest thing to do might be to blow up the TT from A4 to A3 on copier. (If your copier is wired in to C2K then you can print direct.)
But for a TT by form I "print" each form to a CSV file and then assemble them together on a spreadsheet - Monday 1, Monday 2, Monday 3 .... Friday 8, Friday 9 across the top; U6, L6, 5,4 .... 1 down the side. I then print this out on 6 A3 sheets. There is a lot of adjusting row sizes, borders, etc. but you only ever have to do that once - the following year clear all the data on the old spreadsheet, leaving the formatting behind and pour the 7 csv files in. Bingo!
(By adjusting the page breaks, you can get a timetable for each form to fit front and back on an A4 sheet. Magnifying glass not supplied)
There is (or was) a bug in the Nova-T CSV print which inserts an extra blank cell at the start of row1.
Tell us more bout your 19 period timetable - ours is a regular 9 period per day, 5 days a week affair.
-'runner