TL;DR - A different approach calculating strength based on Donchain channels
My approach calculating strength by using the difference between price and donchain average. It is possible to use the highest/lowest value of a given source (like close) or to use the highest high/lowest low (by using the option 'include wicks') for the strength calculation
I added multiple moving averages which can be used in the calculations incl. SMMA (RMA) which is used in RSI calculation and works best for me.
Usage is similar to RSI: DC Strength oscillates between 0 and 100. Low values (<20) indicate a bearish situation while high values (>80) indicate bullish ones. Center line (50) crossings can also indicate a possible trend change.