You may swap activated charcoal for
black (ultra-dutched) cocoa powder (U.S. option
HERE).
You may need 80-120g almond flour, depending on how defatted and fine your brand is.
If you don't wish to use coconut flour, you can simply add enough icing 'sugar' to achieve the required consistency.
The best way to ensure accurate measurement of ingredients is with Metric Kitchen Scales. They are inexpensive and take up very little space. Click
HERE for the ones I use. For U.S. option click
HERE.