Choose by return time
Estimate when you will next open the game and load products that will occupy the machine for most of that period. Save short products for sessions when you can collect them.
Stage ingredients first
A long queue can consume all available cream, sugar or syrup. Produce base ingredients before loading dependent machines so tomorrow's farm does not begin with several shortages.
Leave collection room
Finished goods move into the barn when collected. A nearly full barn can turn a successful overnight queue into a morning cleanup problem.
Do not optimize every machine
Some queues will finish early or remain idle. Prioritize bottleneck machines and goods connected to a visible goal rather than forcing activity everywhere.
The best overnight queue is one that finishes near your return and leaves enough ingredients for the next session.