All you need to do is memorize some equivalents of common speeds in europe.
34 MPH = 55 km/h
62 MPH = 100 km/h
80 MPH = 130 km/h
should keep you ticket free.
And if you have a bad memory, like I do, go to an office supply store and buy a pack of small plastic colored adhesive dots, and put them in the appropriate spots. I did this when I took my Triumph to Canada and it worked flawlessly.
IIRC, the most common KPH's on my trip from Italy to Isle of Man were 40, 60, 80, 100, 110.