Amplitude is a very simple measurement of subtracting the range (high - low) of a candle by some other data from that candle. in this case, we use the midpoint of the candle, so the calculation is (high - low) / (high + low)/2 . This isn't a new concept, but I could not find this study anywhere so I decided to add it myself.
This is a simple script to quickly see changes in % in each candle.
In blue open/close variation. In red Histogram with range between high and low.
This helps me understand very quickly what's the typical change in % for a specific timeframe/pair, so I can fine tune my Stop Losses and Take Profits.