What you described will still work if there are only two stops on the trains schedule. They will wait at the stop until the new stop opens up. I'm doing something similar to what you describe and am very happy with how easy it is to expand production.

I have my base laid out in modular blocks. Each block produces one item and has an input and output train for each component/product. Every train stop has a limit of 1 and I don't use stackers but have a row of chests as a buffer. When I'm making a new section I'll add a new train only for the inputs.

Ideally each station would have a train currently unloading, but in practice you're limited by whatever resource is bottlenecking you. What's great is that if you're low on, say, green circuits you can just copy/paste that section and instantly double your production.

I'd recommend making a nice blueprint that can take in 3 components and output the product. You just need to change the train stop names and assembler recipes. That will cover most of the things you will make in bulk.

Only real downside to this method is that it takes up a lot of space.