I like the TM part where it says "or whatever fits" on the vehicle in the suggested location. Our M220 had several layers of bumper and body markings in its 55 year tour of duty with the military. Most everthing was 3 inch, but there was some 4 inch as well. The last round of markings were vinyl letters and some of that was 2 inch. I think it depends on what period you want to represent and to what ever latitude allowed during that period. We opted for the middle period on our M220 and used flat black 3 inch paint stencils as we found under a couple of layers of later paint. My M37 came to me (back in 1963) with no bumper markings, but 2 inch high flat white vehicle numbers on both sides of the hood. Moosetracks M37 acquired by him at the same time came the same way. Those numbers are still there, but both trucks are very faded now.