sweet potato slips...how long should they be?

Mine have always been fairly long...8-10" maybe.
Then I remove most of the leaves and plant them deep, up to the top few leaves left.

This year I started them later and was able to set the flat and jars of potatoes for starts out in the sun thinking there would be less shock when I eventually plant them.

I think they are shorter slips since they have had that nice sunshine and aren't leggy like when I grow them in the house with much less light.

So now I wonder how short a slip will produce potatoes?
Does it matter?

Sweet potatoes are very hardy and most any slip will grow. That being said, the roots primarily grow out of the leaf axil (where the leaf grows out of the stem). So best practice is to have two leaf axils under the ground and at least one above ground. This gives optimal amount of root growth near the soil surface for tuber production and leaves one above ground for fastest leaf growth. Leaving two above ground is fine as well, but much longer than that and you're just stressing the plant to try to sustain that much more vegetable life before it has roots.

thank you Nathanael!

That's exactly what I needed to know.

number of leaf nodes matter more than length....now to go count them!