Absolutely spot on, David. As for myself, I don't believe I could restore my vehicle without the depth of support from the folks here on MLU.
When doing the signage for my restoration truck I decided on using vinyl numbers for the doors and nose panel. I made this choice based on likelihood of me stuffing up sprayed stencils. The vinyl is neat and consistent in appearance, but does not have the same look as stencilling would. In fact, I think I will use stencils in future, now that I have had a little more experience in last couple of years. If you DO wish to use computer cut numbers/lettering, be aware that both white and black vinyl film are available in matt finish. I couldn't get that at the time I wanted to, so spent some time lightly sanding the vinyl before applying it to the vehicle. Not a fun job. Incidentally, the D ^ D marking on the side curtain curtain was done by stencil I hand made. Not very neat, but functional. Now that I have acquired a sign cutter, any future marking will be done as a stencil. Stencilling is easy if using the right materials. On canvas any vinyl film can be used to make the stencil, because it won't be difficult to remove the film from canvas, but I would be reluctant to use standard vinyls on paint. The solvents in paint may cause them to release from the surface OR the adhesive could seperate from the film, making a real mess on the paint surface. I have had this happen when applying the 9th Division marking on my green truck.
The numbers on my grey truck are also vinyl. I don't have any issue using this method on that truck, because it is not presented with the same desire for originality. It's my daily driver, (well, not literally) so gets knocked around a bit. The second photo above, shows the TAC sign for 29-46 Infantry Battalion. Vinyl film was used here also. I did ask the sign place who did the artwork for me if they had stencilling material, but they did not have any of that material. In fact they had didn't even know of a cuttable material for making stencils! I find that quite remarkable.
The final photo shows the stencil applied to my fuel tanks. I ordered this from a UK business that specialises in military vehicle signage. They offer vinyl signs, single use stencils, and the type I ordered, oilboard. The oilboard stencils are a thicker material, and can be used over and over again, provided care is taken when removing from the surface it had been applied to. The only drawback I can think of is that oilboard is not particularly flexible. You will have difficulties getting this stuff to go round corners or compound curves. For that matter, it doesn't like being applied to rough surfaces either, and may lift up in places during the stencilling process. Another option is a product called Paint Mask. It is thinner than oilboard, has greater flexability, better adhesion, and can be manipulated easier. The down side is, it is a single use product. Not such a problem if you can make your own, and if you need to purchase from a sign company, it shouldn't be much dearer to order multiple copies in one order.