https://harp.andrewzajac.ca/MyHarps

Look at the section marked 'Select blog posts' on the left

I think the most useful for you will be the selection in BLUE but all articles are revealing and worth a look.

• How to play the full chromatic scale on a diatonic harmonica
• Altering Standard Richter to Wilde Tuning
• Marine Band Reed Chart
• Quick Videos
• Opening the back of a Special 20 or Marine Band 1896
• Covid19: (How) should I clean my harmonica?
• A new comb color
• Is a custom harmonica "better" than a stock harp?
• Forget about temperament! Freestyle tuning with the Tuning Card
• The Gapping Paradox
• What happened to breath control in the 1960s?
• Vintage Hohner reeds
• Get a grip! Eliminate the guesswork
• Before & After: Custom Marine Band Reed Plate
• Overblow Science Question
• The list of Hohner Affiliated Customizers (2018)
• The Assessment
• Sympathetic reed work™
• (video) Harmonica repair mistakes! #2 - Embossing therapy
• Extra tips on the use of my comb tool™
• Replace harmonica reeds just like you change strings on a guitar.
• Custom Harmonica Comb - Andrew's method
• How to bend notes on the diatonic harmonica: What is “Bending Energy”?
• More Better - ultra precision tuning
• Mysterious embossing instructions
• Tweaking harmonicas: Measure what you change
• Playing a harp while giving out advice
• Video: Replace Marine Band nails with screws and install new comb
• Making a Lee Oskar harmonica play overblows
• The French Tuner™
• Tune a harmonica using your ears and a simple chromatic tuner
• Pentatonic scales - Play in six different keys on one harmonica... With no overblows!