I always make sure that there’s a good bit over away from the start edge of the graphic so that you can fold it back on itself and give it a good yank. Then when the filament reaches the edge of where you want it to cut place your thumb on top so that it starts cleanly. Difficult to describe. Could do a video but don’t want to teach granny to suck eggs. LOL.
It isn’t cheap but you should be alright if you build it into your costs. The customer should not even notice. Plus it’s way cheaper in your time than cutting templates and the like.
I would also suggest trying a filament cutting tape like 3M knifeless-tape or wrap-cut tape on a job like this mate. I appreciate the tapes can be a bit temperamental at times and even flawed in some ways. but they do give the best solution to a job like this.
I’m the same don’t like the knifeless tapes. I would trace one side and scan it in and smooth it off till you’re happy. You then only have to mirror it for second side and you have it forever backed up, would think that’s quicker anyway if you have 3 to do.
Simple advice but I always find when using cutting tape that it’s best to leave plenty spare and get it started at both ends if possible before applying your material. That way if the tape messes up when starting it you can reapply without trying to get it picked out from under your graphic which is a real pain in the ars*.
Unless you get an actual vector template for this vehicle to plot/cut the stripes. the only other way to do this is trim the vinyl on the vehicle by using trim tape under the vinyl and cutting with a scalpel. not recommended!
I would agree with everyone else, go for the knifeless tape option.