I can confirm boldly that the three of them used together can be quite advantageous. I use the memory palace when I tried to recall practical processes. It's like a video stick in my head and I get to revisit it.
The second principles still helps me to this day in solving maths problems. I learnt tbe technique from a friend in further maths classes and it has been helpful to me since then.
The last one is focused on repetition. I believe everyone is well familiar with this. Reading the article refreshed my knowledge in the application of these techniques in the University, I needed it.