Don't smoke it all after the first week. Let as much of it cure for as long as possible for best taste/smell.
Also the first week of cure activates the THC to get you high. Before that it won't work that great.
He probly got 1.5kg Wet weight on 80% of his plant.
1/5 of 1.5k is .3
So we'll say 1.8kg Wet weight, and 25%-33% of that is going to be
.45 - .6 kg dry.
So about 1lb-1.3lb if I did all that math right. But I am smoking a bowl, these were random estimates, and there's been no clarification on what his 1.5kg measurement was. Also if he measured the plant in the first two pictures on the thread, then that includes a LOT of stem/leaf weight.
Hanging a plant upsidedown is simply convenient. It doesn't make the buds bigger or better at all in any way.