1) After identifying the entry candlestick (buy), I want to place a fixed sell one tick below this candle. (my stop loss)
2) My target is fixed and is defined by the size of the entry candlestick. In this case, the size of this candlestick multiplied by 2
This is interesting. As of now buy, sell, short, and cover signal definitions are independent of each other. If I understand you correctly you want to use buy price value in defining sell signal, right? This is not possible as of now but I can think of the way how to make it possible. Please confirm if I am getting you right.