CSST Gas Line is a Couple Feet Too Sort
To close this out, I had a friendly, professional, licensed plumber come out and make the change and it set me back all of $110 + a $20 tip. In retrospect, there was no reason to be concerned about cost and every reason to pay a professional. Sharing this in case it's helpful for someone else facing a similar situation.
Editing to add details: The plumber used all existing lines. He added a few inches of slack by connecting to one of the manifold fittings that was just a tad closer. I'm not certain, but he may have also swapped out the &quot;short&quot; line with an existing line that was just a tad longer.