First, center your model as best you can in the graphics view of Fusion, and be sure to zoom it in as close as you can while still being able to see everything.
Once you have this done; Select the setup or the operations you are wanting to post to a setup sheet.
Now instead of hitting the Setup Sheet button on the Actions panel we are going to click on the Post Process button.
This will bring up the post process dialog where we will filter first for Setup Sheets.
Then we will select the Setup Sheet post processor that will output the HTML file.
Once selected, the properties window updates with the user properties that are built into the setup sheet post processor. In this dialog we want to look for a property called "previewWidth".
Modify this value to a size that you would like to see on the document.
Special thanks to @frankthecncmachinist for suggest this as a blog post!!