If there is any way you can make a screenshot later i would love to see it, as i can't quite picture it in my head. But I'm going to try to keep basically this entire post in mind as i move forward.
But yeah definitely gonna try and make those sprites a bit better, though i have a band aid implemented for 0.4 that makes it obvious what items you need (they're named both in the resource... tree? view? i don't know and in the upgrade menu). But yeah it was bronze you needed.
Game Dev Rant (i think?) Incoming, TL;DR I need to change a lot of things and rethink splitters to fix this but i am going to try. And hopefully it will work.
The biggest problem with your design (well actually the games design as i want people building interesting solution's like yours) is that it's 100% grid based. I can't change this fact but it's awkward to work around, and why belt's feel slow. In Factorio belts aren't quite grid based and thus can carry 3 more items. That and they're smaller than in Manufactory. which makes them much better in Factorio than in Manufactory.
The second biggest problem (or maybe this might actually effect it even more, i don't know) is that the whole game runs on a timer, meaning every block has a minimum amount of time they can do stuff in. Conveyors run every time the timer hits. Meaning they are the fastest thing in the game.
This effects splitters as it is literally impossible for them to move items at the rate they're supposed to (they won't fill lines unless you block off both exits. Which is obviously useless) because splitters need to be faster than conveyors, yet conveyors need to be faster than splitters to deliver the items, i also don't know how to use Factorio for reference in this case cause i have no idea how it works in Factorio, it's like magic. However the thing i mentioned before about making everything slower and speeding the game up would help solve a part of this, and a redesign would hopefully solve the rest. So i'm hoping that i can get this fixed quickly.
By the way was this rant too much or was it fine, should i just explain things simply or should i keep this complex explanations in (because i like doing them)