Too risky for several reasons: smoke, danger of fire, neighbors or other people, building substance of the balcony, material of the tent.
You need a place where you can light the BBQ outside and bring it into the room when the coal glows well and evenly and where no one can disturb or finds you until you die.
If you have SN, it´s not a problem to get an antiemetic.
https://sanctioned-suicide.net/threads/charcoal-method-advice.94265/#post-1655792
https://sanctioned-suicide.net/threads/failed-attempt-with-co2.95494/#post-1672849

CO guide short version:
You need:
a high quality(!) BBQ + at least 135 g of high quality(!) coal per cubic meter of room air + BBQ lighter + parcel tape or insulation tape + if possible a CO meter that goes up to 10.000 ppm or higher. I would even use two BBQ´s, each with the required amount of coal.
Seal the room perfectly from the inside. Light the BBQ outside. Bring the BBQ inside when the coal is well glowing and no longer smoking.
Put an info on the outside of the door:

Danger carbon monoxid

. Wait until the CO meter reads 10,000 ppm or go into the room immediately.