a button to change compacting behavior

• all
  current behavior
• only overflow
  only if source item slot is full
• balanced
  only if more source than target items
  or if source slot is full

in case of multiple source slots

• use memorized or first slot as source
• use all other slots like overflow

Could you actually give me examples of why this should be added / when/where this would be helfpul?

where:

• sending output from sieves/farm into a barrel
• items are packed to save space and to keep packed variants available
• e.g. diamond/diamond block, redstone dust/redstone block

current/all behavior

• all source items will be packed
• but to get more than 3 or 8 of source item you must unpack target items
• good if only target item is relevant

overflow behavior

• source items will be packed, if source slot is full
• but target item only available if source slot is full
• good if mostly source item is relevant

balance behavior

• will only pack source if more source items than target items
• good if both items are necessary

additional a "keep 1 stack" could be added to the list