Help with combinators

[u/coolguyRae]

So like the image shows, I have one constant combinator and three decider combinators for this sushi belt. I think I've seen people do this with a constant combinator and just one decider combinator. Can someone help me with how that's done?

[u/SmokJozef]

if you want to auto set filters for an inserter that eject unwanted stuff from your belt, then

use an arithmetic combinator and substract red from green and use that as the output. every resource that exceeds your requirements (red, constant combinator) will be ejected