you'll never get it right from a photo, as you only have like a 1/8" tolerance before you're screwed in either direction.
trace letters onto acrylic, drill the inner corners with a 1/8" bit before cutting with jigsaw (else chance having shatter-points where jigsaw lines intersect)
...if you're replacing faces that no longer have the acrylic letters available, then use a piece of coroplast, or better yet the piece of acrylic you intend to use, to span the can and trace.