Honey and coban on split or broken stems works like a charm; bamboo coffee stirring stick for a splint if needed. I leave it on. When I harvested my first grow (tent) recently, I took off several that had to be fixed to see how they came back together and it was amazing to see how well they repaired my screw ups. I accidentally broke a fairly substantial, loaded stem late in the grow and thought I lost it but it never even wilted with immediate care.
This was not an autoflower grow. So, may be different with autos due to their short growing time. Will be curious on that one as I just started some autos in the tent.