That is quite a bit of work to do that many parts regularly, on a manual lathe.
Finer pitch (UNF) would be somewhat easier, except you most likely would have to bore the tube to obtain the proper starting diameter. That will take some time. You could probably rough in the UNC thread in the same amount of time, and then finish by hand. The roughed in thread will make it possible to start the tap without a guide, and you can probably begin with a 'plug' tap, instead of the 'taper' tap.
I would arrange a secure workbench, and a pipe vise to hold the roughed in threaded tube. Then, devise a very long handled wrench, that two guys can walk around and finish the thread.
Don't sweat it, use as much leverage as is necessary to make it easy to turn.
Is farming the work out to a cnc job shop not a possibility?
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)