It's very similar to yours, with some interesting features you may want to consider (composition of multiple request presets, trashing of negative requests).

https://mods.factorio.com/mod/Logistic_Slot_Manager

I haven't actually seen that one, probably due to filtering to version .17 when I went looking for logistic mods. Combining requests isn't something that's crossed my mind before but definitely could be useful, perhaps I'll look at it while I finish sorting out the UI as I'd need to rework the selection menu to allow selecting multiple requests. Trash setups I can look at too, they should work pretty similar to regular requests, thanks for the ideas!

https://mods.factorio.com/mod/LogisticRequestHinter <-- this might be interesting, too
https://mods.factorio.com/mod/AutoTrash <-- also, this

https://mods.factorio.com/mod/LogisticRequestManager
and this one ?