Nope. You don’t have to eyeball the first important cut at all.
Layout your file to the exact measurements of your desired material. Cut jig from cardboard or other waste material. Back Desired material up to your jig. Voila.
Like so:
https://community.glowforge.com/t/alignment-of-irregular-objects-coasters/16116
I just used this technique today on a small piece. It’s rock solid, accurate to about a kerf if done correctly.