I just wanted to come back and thank all that contributed. I didn't post much here to avoid interfering with the discussion, but I've read and reread the whole thread many times, trying to figure out which design(s) to use "most of the time" even though I know I'll come back to both this and Eradicator's thread over and over for scenario-specific designs later on.
For now, mainly due to compactness, I am testing the following in the unloads for my main bus. I'll report how they work as I use them through a build from the early low demand phase to the late high throughput space science phase. I am actually moving the smelters to their own outposts so that I just measure how these unloaders work with the bus demands, by unloading smelted products.
The tests will be done with 1-2 trains. Also, please keep in mind that I am still trying to fully understand how these balancers work, some of it is still Greek to me and I will almost certainly make some wrong interpretations and adjustments.
- DaveMcW's unloader with an 8-8 balancer. It lost some throughput due to the balancer, but worked reasonably well. It didn't unload quite 100% evenly but seemed to keep up OK. The main inconvenience was bulk, this used lots of space.
- Durentis unbalanced splitter trick unloader from Eradicator's thread (similar to Nog's in this thread but unloads with 6 splitters per wagon and produceds 4 belts) taking the belts from each side of the 1-2 train to a 4-4 balancer. I am hoping that by unloading a set from one side it will prevent train delays even if the chests get unbalanced. This one is quite compact and looks promising for unloads where I feed 1 train to less than 4 belts.
- Eradicator's final bot-based design, although I wanted to unload from both sides of the track so I placed the passive provider chests on both sides of train. I setup 4 roboports and fed it 200 bots. I hope I didn't mess up his design.
- Durentis final bot-based design, although I could not handle the "lots of track" on both sides of the track. So, I removed the tracks from one side but kept his Passive Provier, Active Provier and Buffer chests, to make the bots go "deliver" to the other side. I probably botched his design by doing this, but we'll see.
The bot-based designs are looking very attractive. They are much more compact and don't waste space or throughput as they should not require additional balancers. And except for some low-throughput train stations (like for uranium ore) I think I can get the necessary advanced chests and nuclear power going before even starting the bus and these "feed the bus" unload stations.
If you think I'm interpreting the discussions, advantages and disadvantages incorrectly... please let me know, perhaps with an explanation to help me understand. As long as I am getting good advice I don't mind being called an idiot
NOTE: Edited this post after laying down my test unload stations. Much more relevant now.