Yeah, you got this. It is really not that complex, just the consequences of goofing can be severe, like aviation.
Racers say "speed costs money, how fast do you want to go?" One thing maybe to consider is that you are not requiring that many rounds, but probably still want to minimize how long the task takes. And added features make it easier to go fast, but they also make it more relaxing. Also, like vehicle towing capacities, output tends to be overstated, so having a faster press can make it a walk in the park instead of a sprint to the finish. 400 rounds in an hour puts you into progressive territory, additional features would include:
Auto Indexing
I didn't think this was a big deal, until I had it. IMO it really helps keep a rhythm. It might make it harder to learn on, but not as hard as building a 1911.
Case Feeder
I didn't think this was a big deal, until I had it. Not taking your hand offa the handle probably doesn't seem like that big a deal, but taking it off the handle, then finding and orienting a case, then placing the case, then finding the handle again, while you are also finding, orienting, and placing the bullet, is a pretty big task load to eliminate.
Bullet Feeder
I have stopped short of this enhancement, but I have been tempted, those 115g round nose 9mm bullets are slippery little bastards...
With my press that indexes and has a case feeder I have timed myself as being able to load 100rds in 6-7min, but that is from the time I touched the handle until the buzzer says I need more primers, and that is not the total picture. From the time I turn on the shop lights until I have a can with 1k in it is gonna be a couple hours, not so far off of your target of 400rds/hr. I am also not going to feel like I just wrested a bear or something. And I also almost never thrash them out like that anyway, more like kicking out 2-400 while my wife watches something on TV I don't want to.
Also, I do not want to be That Guy that pushes what they have because they think they are so smart that everybody should do what they do, so I am trying to not make this brand specific, but my experience is mostly with the Dillon products. But some of the Lee stuff is really a strong value, and their new Pro 4000 indexes and has a case feeder and four stations and costs less than the Dillon case feeder! One thing though, the Lee Loadmaster seems too good to be true, and when I tried one I decided it was.
And @olstyn mentioned loading one at a time on a progressive, that is absolutely true and good advice, and a Hornady advantage. Dillon's 650 didn't work well like that (it feeds primers on every stroke) but now that they evolved to their 750 it would work that way.
I would put this wayyyy down the list if things to worry about. They almost never end-of-life products, and in those rare occasions they continue to support them, and the dies are not likely to be what might break.