It would be nice if it could output how many spaces it can plant on and how many plants are growing / empty

So you can tell exactly how many seeds you should send to each tower

This should be already doable with vanilla circuits. The number of of trees growing can be counted by a memory cell -- counting up when a seed is planted, counting down when fruits are harvested. See this blueprint:

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Total spaces is constant, emtpy spaces = total spaces - occupied spaces.

The reason this mod only counts matured trees is because if I wanted to count any tree, it would already be doable vanilla. I mean having the ability to count any tree in this mod is still nice to have, but it's not a priority.