It's time to look at the options for unified trees. I'll save the RootsMagic/FamilySearch sync for last.
First, Geni.com. I entered my Smiths, and when I got to great-great-grandfather James Smith, I was told that there were 40 possible matches. I then entered additional data (a date and location of death), and the number dropped to 20. However, in order to see those, I would need to be a Geni member. So I'll hold off on that for another future date.
Next up, WeRelate. I first searched for each of my Smiths to see if they were already there. None appeared to match, so I began the process of adding them. It took me a few minutes to master the system of adding pages to the wiki structure, but eventually I was able to add my Smith line and come to a reasonable conclusion that these individuals were not already in the WeRelate tree.
I next went to WikiTree, where I had some time ago entered my own name, my father's, and my grandfather's. I now focused on adding Charles Henry Smith and James Smith. First, I searched for Charles Henry Smith (basically, anyone with a real birth year within 2 years of my great-grandfather), and there were no matches that would have been him. I did the same for James Smith, and again, didn't see any obvious matches.
Finally, I created a new, empty tree in RootsMagic, and then downloaded 10 generations from my tree in FamilySearch. There was an error message at one point, but it appears that it successfully pulled down a copy of my tree. I went back to the tree on FamilySearch that I had worked with previously, where I had entered all of the direct-line Smiths, and had processed possible duplicates. That left my immigrant ancestor, James Smith, with 15 possible duplicates. So my remaining task before I leave the Smiths is to work down that list and merge my James Smith with duplicate men. Update: I reviewed all the possible matches and determined that conflicting information or insufficient information could not justify any matches.