Just posted an update. I added a main body for the JGY-370 motor. The center hole has been enlarged to 15mm to account for the various shaft coupler options people are using.
I also added the rest of the drop tubes. 6, 8, 9, 10, 12 and 13mm are now in there.
I do have my doubts about the smaller motor working with the larger feeder. I will be interested to see the results when someone tries it out.