With the fading popularity of kit decals for AFV models, there are several alternatives on the market.  Dry transfers are easy to use and come in a variety of flavours, but have a shelf life and some can be thick.  Another alternative is spray through masks, these can be of the flexible vinyl variety such as Eduard’s Express Mask line or etched stencil products like Tech Star’s latest release.  Tech Star’s set features numbers 1-0 in two rows for either 2 different number widths or for doing both the outline and inner portion of a number.  Obviously a flat surface will be helpful when using these etched masks.