I just had to do the same thing last week!
First of all, use the FIT TO: SCALE option in the FILE + PRINT panel with the SCALE set to 100% for full size.
I like to add a horizontal line and vertical line of some known length that I can measure to verify the plotted template.
My experience has found that most plotters and printers do not print that accurately. So, take that 100% plot and measure the lengths of those known lines. Calculate the SCALE [ (TRUE LENGTH / MEAS LENGTH) X 100 ), and plot again with the calculated SCALE.