I found that youtube channel recently. Really enjoy his videos and impressed with his ability to offer advice respectfully to any skill level. Not to even mention adjusting suspension by reading the tire primarily. Good stuff!
Last year I was having issues with the HP4 late in the year at T-Hill. I went and dutifully stood in line. There was only 1 person in front of me. 10 minutes later, I was still waiting but after listening, I thought I had heard enough to point me in the right direction. I added a couple turns of preload and it helped enough that I paid him his 1 time adjustment rate the next time I saw him even though he didn't actually work on my bike.