Which is the minimum recommended clone height?

How are you propagating the clones? With an aero cloner, you can cut them pretty short…. Plugs need a bit longer…

Tomatoe, Tomato. Last I checked the recommended was 2-3 internodes, you can take tiny ones but will be much harder to get to reroot, all starches/sugars from photosynthesis are stored in the stem until night arrives and it is sent to rootzones, make sure to take cuttings after a long day of Photosynth, the stem acts like a short term battery, the more stem you cut off the bigger battery you will give it to rebirth the rootzones, all leaves except top 2 should be cut to give the best chance of survival, every living part of the plant that stay attached will act as a drain on that battery and we need to save as much as possible for those rootz. The big strong stem will have the new clone up and running in no time. Taking small cuttings reduces the chance of survival, and requires fine-tuning of the environment, sometimes no matter what it just won't grow, I personally try and use blue light once stabilized this reduces internodal spacing, it takes longer to recover but in the long run you will be thankful. Take 2 weeks into flower to monstercrop, throw it back to veg cycle.

Clones can take from 7 to 21 days to root depending on environmental conditions and genetics/cultivar. Ideally, you want the plants to finish at approximately 60cm to 90 cm tall, so you will induce flowering when plants are approximately 30 to 45cm tall.