who is blasting it?
who is cutting and applying the mask?
who is painting it?
how familiar are you with the process?
There are several steps, and there are multiple options available at every step of the way.
it should be designed similar to a vinyl sign in the sense that you objecting should be an effective sign that meets the needs of the client, which should be discussed & in some cases identified by you, and taught (sold) to them... but in all cases should result in a legible attractive & durable result.
If you understand the process then you won't allow the design phase to make cutting, weeding or applying the mask impossible, nor will you create painting nightmares, unless that is unavoidable & you charged accordingly.
If you don't understand the process, or the optional masking materials, application methods, & paint vs. masking sequences... then this thread needs to assist you with that information first... but if you already know that... well, you probably wouldn't be posting this if you did, but tell us how much you know, so we know where to start helping...