Need help choosing the right DERMMATCH color

[Fandreas]

Hello there.
I'm new to the forum and I was hoping I could get some help from people who have experience with Dermmatch.
I've never tried concealers before but I've read great things about this product so I thought I would give it a try. It's really hard to determine which color I should go for as I'm having a hard time determining my own hair color.
I've dyed my hair black for about 17 years, so I'm not used to my natural color.
In some light it looks blonde, in sunlight it's sort of reddish, but mostly I think it has some grayish brown hue.

Here are some photos.

Blurry photo showing the hair density, about 20 days after a shave


About 40 days.


A photo from last summer, before I shaved it all off I had long black dyed hair.
The roots look a bit red in sunlight.



Judging by the digital samples on the Dermmatch website I would say I'm closest to their dark brown as their medium brown looks a bit too red and the light brown a bit too blonde. It's hard to determine from photoshopped photos though, so I'm really hoping someone experienced with Dermmatch could give me some pointers.

https://www.dermmatch.com/faq/

Thanks a lot!