
I just finished designing and testing this smelting array.
It produces 1 fully compressed blue belt of iron or copper plates.
Image of the full array is here. I didn't post it because it's quite tall.
Since it uses only 9 smelters, I hope that it will be more UPS efficient than the previous designs I've been using. It does use some extra fast inserters though so perhaps that will negate any benefit, I'm not sure.
It's quite narrow (pitch of 6 tiles) since most of my late game smelters would benefit from being narrower tiles and it won't make any difference if they're a bit taller than usual.
Blueprint here: https://pastebin.com/DcNy6UB8
If someone has some suggestion to improve the design, or knows a better one that achieves similar goals, please let me know. :>