need advice on mixing colour

hi guys, thankfully found this forum so hope to get some advice. i have naturally strawberry blonde hair which i dont like even though others like it. iv been dying my hair for a few years. ive been all different colours-blonde, light ash brown, dark ash brown, black but to be honest have never been happy with it because my hair has red in it and it tends to shine through after i dye it brown and also the dark ash brown dyes went too black on my hair. i decided to buy a few igora royal shades and some concentrates so i could experiment and do some strand tests.

so i done a strand test with igora royal colour 8.1 (light blonde cendre) and mixed it with IGORA ROYAL anti red concentrate 0.33(which has a green base) and developer 3% all in a ration of 1:1:1. the bad news was that the hair went dark very quickly but the good news was that there was no red tone to it! so i def think the anti red concentrate is good but the ratio i used it in has made the hair too dark. do you think i have mixed it right by doing it a ratio of 1:1:1?

iv done my hair with an 8.1 before without the concentrate and it was not as dark as this, in fact it never really had a great effect on my hair before, the colour still looked the same. should i not mix as much of the concentrate the next time as i feel this is what has made it dark looking? i want something a few shades lighter as its too dark?im looking for a light ash brown.

do yous think maybe i should try 30ml 8.1 with 30ml 3%developer and only 15ml of the 0.33 concentrate. so in a ratio of 1:1:1/2 or should i get maybe a 9.1 colour with the 3%developer and concentrate in a ratio of 1:1:1/2? help? xx