Combien de grammes a votre avis ?

depends on how well you filled the area. height of plant doesn't tell much. 1 to 1,5 gram per watt is a good goal for ambient co2. you get much more then that you probably have a large proportion of laf. More efficeint LED hit 1,5+ much easier. Some less efficient ones probably cannot reach that high. Even with a shitty LED you can probably hit 1g per watt. but, if it's mostly empty space won't be anywhere near that.

Hard to say, you've done everything training wise to increase yield. You're using a hps bulb, always serious power. They are only just starting to flower, they are decent sized plants at this stage, alot of time left. But its not unreasonable to expect 2oz 56g dry from autos, but then some autos will give you less than 1oz, to hard to judge at this stage pal.