I bend stuff like this all the time, and I use a hossfeld bender. They cost $800, with basic tooling.
I have had mine since 78, it has paid for itself about a thousand times over.
It has stops for degree of bend, and for length, you do a couple test pieces, then bend 100 of the first bend, reset the length stop, bend the second, and so on.
The mickey mouse chinese benders will not do 5/8", and probably not 1/2" very well. A hossfeld will do 1", no problem. It has a 4 foot, and 8 foot extension handle.
Its a well designed tool, and well worth it if you think you will be doing fab work for a while.
Heat and bend, 400 corners, sure seems to me to be more than a couple hours. With 5/8", you probably want a helper to hold the rosebud, and nice big tanks of oxy and acetylene. I would be amazed if you could do em in a minute, probably more like 2 minutes per bend. Thats 800 minutes, with no pee breaks or lunch. About 2 days.
With a hossfeld, maybe 2 or 3 hours.
I bend hundreds of pieces of stainless round bar all the time, and have exact matches on length and degree of bend with the hossfeld.