Diatonic harmonica customization was much harder when I started because there was so much bad advice.

Thanks to U.S. trade policy changes -> "trump tariffs", lol - using certain materials has become unsustainable for small businesses like mine. So I’m making a change.

Some of my tools will now be made of 6061-T6 aluminium. It’s a smart, earth-friendly shift.

An analog strobe tuner like a Peterson 490, Peterson 450, Peterson 420 or a Conn ST11 all use a rotating strobe disk and light flashing at the frequency of the pitch you are playing to show you what you are hearing. You can see more than one note at a time and you get to see how they are, relative to each other.
You are tuning sound at the speed of light. That's something no other tuner - even the so-called digital strobe tuners can't do. They work at about an interval of 100 milliseconds. That's why the needle or any other form of display is so choppy.

Making both reed plates flat is one of the easiest things you can do to get more power and better control of your harmonica. It's very effective.

All my kits come with some version of the reed plate claws. They are the tools I use to straighten reed plates on my custom harmonicas.

A cover of my favorite song.

Just about everything you do to a harp affects the tuning so it stands to reason the last thing you should do is adjust the tuning.
But how do you make adjustments to the tuning without messing up the shape of the reeds or undoing other hard-earned adjustments?
To lower the pitch using a file, you can support a blow reed while the reed plate is still on the comb using the Hockey Stick.

That's a good question. Whether getting a custom harmonica as a rank beginner is a good idea or a bad idea depends on your goals. If you don't really have a clear sense of your goals, then this might be an opportunity to think about them.

"Recently, the price of Grobet files has exploded. I can't afford to put them in my kits."

A file is my preferred way to tune a harmonica reed. With good support of the underside of the reed, you can raise or lower the pitch by a whole semitone without changing the shape or affecting the performance of the reed.

I've been using 0-cut Grobet files which are Swiss type.