Best way to prioritze Belted fuel?

[Peter34]

Let's say I have a Belt of Solid Fuel and another Belt of of Coal. As much as possible, I'd like to feed the Solid Fuel to my Boilers, only using the Coal if I run out of Solid Fuel.

I know I can use a huge and complex system of Inserters to first stuff Solid Fuel onto a belt, and then downwards of that I can have a similar system of Inserters to stuff Coal onto the Belt. If there's Solid Fuel on it already, these new Inserters won't be able to feed the Belt, and the Coal doesn't go onto it, but if for whatever reason the stream of Solid stops, then they'll start feeding it coal.

The problem is, all those Inserter actions takes energy. I'm frugally inclined. In some ways, anyway.

I've tried a Splitted, but not very surprisingly if a Splitter is fed one line of Solid and another of Coal, and only one Belt leads away from it, it'll mix the Solid and Coal evenly.

I suppose if I use a "funnel", starting with 4 Splitters, combining into 2 Splitters, combining into 1 Splitter, then I can achieve a sitaution where only 12.5% of the items fed onto the final Belt are Coal, the rest being Solid. I could go bigger, 8 Splitters gets me down to 6.25% Coal, but I think that'd be excessive.

Are there any better ways of achieving this, without using a lot of Inserters? (Note I'm asking about alpha 12. Alpha 13 might offer new opportunities.) Basically a way to prioritize what goes onto a Belt.

[codewarrior]

Like this?

t-bone it.png (463.11 KiB) Viewed 6018 times

[Peter34]

Yes. Thanks. I feel rather stupid now...

[Xterminator]

Lol I was just about to suggest that same thing. Don't feel bad, sometimes the most obvious solutions are the ones that just go right by you.