Personally, I feed same color, 1x hero at a time ( only 1* / 2* ), until special skill is 8/8. Then same color 1-10 heroes at a time ( 1* to 4* heroes and 1* to 4* Trainer heroes).
This increases the chance of a hero stuck without 3* / 4* ascension items will still be 8/8 special skill.
Saving food
It is to save food.
But.
Because you have limited hero slots, it saves very little food in the end ( see notes).
Unlucky 3*
@Rook had a Gunnar 3/8 3* 3.50. With the new system you might save same color 2* since they are +20% skill roll when used on a 3* 3.50 that still is not 8/8.
Notes
Click for notes
Some info early on in the thread is outdated, but math is still good
