So, back to OP question, IMO… level on rainbow, so red feeder goes to red, etc…
Priority left to right in order
Red: Boldtusk, Wilbur, wait for Scarlett or Kelile
Blue: wait for Grimm, Sonya, Gunnar, Valen, Ulmer, Nordri, Helo, while waiting I think Frost is great fast minion at 3.70 is playable, Jarvur is so so… Boril is okay for map S2, etc.
Green: Caedmon, Skttleskull
Yellow: Kvasir, Li Xiu
Purple: -