Frequently off center

Easel Easel Pro
21

You can if you want to, that is perfectly fine.
As long as the center of your design in Easel is centred around its grid corner and your bit is indeed centred over the material it will carve centred. You use this center position as your Home Position which Easel ask you to confirm before the actual carve begin.

Take a look at this video which elaborate on these issues, made by @PhillipLunsford : https://www.youtube.com/watch?v=vgjZk3YcxaM

22

In Easel material zero is always at lower left of material.
Your image above showed what the result was going to be if you positioned center of art at 0,0.
I looked at the link to your project and it was pretty good and no reason for it to run of right or left edge. However was a little close to the bottom.
You have to be careful about text in Easel. There is a bounding box around the text and can scew the centering.