in terms of 2,there is an in game solution:
This set up operates differently under different conditions:
- if both output are empty: then the top will take 98.5% of the items while the lower only takes 1.5%
- if the top is blocked, then the out will take the full 100%
This is similar to the priority splitters that you wanted just with a little leakage
You can sacrifice more leakage for less space by including less columns.
I didn't uses this exact design but similar principle in many places in my factory with often a 1:7 ratio instead of 1:63 ratio and it worked pretty well.