Here is the bottle I used, and some mixing guidance.
The bottles are 50ml each. I used 2 for 100ml. I didn't connect the syringe. I can turn the bottle sideways and gently squeeze out one drop at a time.
This is a direct link to the bottle on Amazon, available in the US (no referrer link):
https://www.amazon.com/gp/product/B07VVCCHQ9/
Syringe Bottle with 20G Dispensing Needles and Cap (50ml Dispensing Bottle)
The mix:
Industrial grade MB powder worked fine for me and was easy to get, and I figure this disease is taking me faster than any heavy metals that may be present. You can be more cautious with a USP or lab grade of powder.
To mix up the base dilution, I combined 100ml hot water from the electric kettle and 1gm Industrial grade Methylene Blue powder into a pyrex measuring cup, and stirred well. It mixed in completely almost immediately.
I used a gram scale (which most won't have) to measure 1gm of MB powder . I will come back to this post and add an approximate volume measurement later.
Be very very careful, the powder and concentrate stains
everything, and wiping with water just spreads it out. Perform your work on a stain proof and non-absorbent surface (even my stainless steel sink stained because it was textured, as did my wife's white marble countertop - oops!).
Final dilution guidance:
I add 5-15 drops of the base dilution to cold water (no specific amount, generally about 1 cup water) in a steel cup as it washes up easier - glass should work as well. It will definitely stain plastic. Don't forget the rinse will probably stain your sink so run your water continuously while rinsing.
The final diluted drink is very dark blue and highly bitter, and you will probably worry that you just poisoned yourself at the first taste - I know I did. This will mean you probably did it right. The safety factor is very high with MB, I couldn't find anything that indicated an overdose amount, so it seems an overdose is hard to do.
I read on-line that Vitamin C as Ascorbic Acid removes the color and it should still work the same.
-Ken