Udo: It was just like you said, trial and error. My first attemp was just med ash brown (way too dark). My second try was med nat brown (too much of a reddish cast). My third try was med ash brown and light nat brown (again, too much of a reddish cast). My fourth try was med ash brown (3/4) and light ash brown (1/4). Perfect match then they discontinued light ash brown. I always choose 2 and 3 shades lighter than my natural color and mix the two shades. The HS golden shades are suppose to cast a light golden shimmer to hair. The natural shades will cast a reddish tint. Not sure if that helps you or not.
And, hopefully my fellow curlies will chime in here.
3B Fine (lots of it), Normal to High Porosity
Low Poo: Elucence Moisture Poo, Renpure Organics
Co-Wash: Tresseme Naturals, Giovanni TT
Rinse Out: Biologe Cond Balm, SS Deeply Decadent Moisturizing Treatment
Leave-In: Oyin Hair Dew, CJ Beautiful Curls,
Stylers: SS Curl Enhancing Jelly, SS Firm Holding Styling Gel, Jessicurl RR and CC, BRHG, Biolage Gelee
Extras: ACV rinses every couple of months