Do factories need to be load balanced?

[fringe heath]

I have a number of blueprints that process all 12 (4x3) lanes. Some of the lanes have shorter paths through the blueprints than others. When a factory has several of these blueprints in series, the lane length difference can be a bit noticeable.

I'm nervous that factories with blockable components, like stackers which require shapes on both lines, might end up stalling because one of the inputs has gotten so far ahead of the other (with a longer lane length) that the entire factory stalls.

Is it a "thing" that factory line lengths need to be balanced?

I feel like the above described factory stall really shouldn't be possible, but when I see trains waiting at wait loading station stops with some lanes full of boxes, and others empty... well I get nervous.

Thanks for any tips and insights.

[uncut parrot]

Stalled factories are unlikely to happen due to the linear nature of factory flow. While it is definitely possible, I don't think you need to worry. BPs designed to handle 12 lanes (at full throughput) will always reach maximum speed eventually. Shapes reaching different parts of your factory at different times will be a regular occurrence, as you will be transporting shapes from various distances. But once everything is "warmed up", it should run at full speed (assuming all your platforms are properly handling all 12 lanes)