At that height, I would use a pounce pattern and chalk lines.
A projector would require a lot of up and down on ladders or scaffolds and still might distort.
I can't see the length of the thing or the height of the letters.
Cast vinyl would be an expensive PITA, a paint mask would be a pain too and cost way more.
Client would be responsible for primer coat.
I'd probably use Ronan Bulletin enamels or else Novacolors.
As an example of price, I got $2500 for this job (covering old sign) and it was about 16'x12' with more colors than just black, and this was over 2 years ago.
Love....Jill