Wyckoff trading method, page-1831

That sounds like a terrific experience, it really is a beautiful place. You must be pretty fit to hike over that country. I just trend to indulge the Tamar Valley treats on my trips.
Nice to hear you're reading Du Plessis. With the modern approaches to Wyckoff you can get by without PnF but it does broaden your understanding of Wyckoff's work if you study it.
I used Amibroker to program my PnF. I looked around at various software but it's either expensive subscriptions or just out of whack. One of the more frustrating parts of the journey. I believe Pro Real Time has good starting point that is reasonable for no outlay.
For my box size I use Du Plessis' logarithmic approach with ATR. I use rounding which I've programmed into the charts, an ATR of 0.236 becomes 0.25. I have several charts set to 2x, 1x, and 0.5x of ATR and I calculate using High/Low rather than the Close, also perferring 3 box reversals. Most of the time I find 1xATR box size gives me good "form", not wanting too much noise where you could just use a bar chart, but also not too little that there aren't enough figures. I've programmed my software to let me to double click on the start point and the end point of a congestion area to automatically estimate the "effect" of the "cause".
PnF is an art. It takes a while to get the nuance. The constant battle between supply and demand distilled down into its purest form — X versus O. Beyond Du Plessis, Section 7 in Wyckoff's method of Trading Stocks Div 2 — Judging Strength or Weakness by the Half Way Points is a short but sweet chapter that gives good insight in how to use PnF to understand supply and demand.
To be honest I don't use it for all trades but I do find myself referring to it to create a more informed picture without it feeling like a confirmation bias.
Cheers.