goldwell topchic versus elumen

Hi all -

i'm going to go from dark blonde/light golden brown (colored ligher from my natural level 6 ashy color) and i want to go red...mainly dark auburn but with a little copper/red kick...

i know all the problems with reds fading and i've been hearing great things about goldwells non-fading reds...there is 1 salon in my town that uses goldwell color. having said that, if i want to do it myself, i am surely confused about goldwells letter designations (even though i've read claude's help)

so to go from around a level 10 on a regular hair chart to a dark auburn (33 or 35) on goldwell's chart - would i do a level 6KR?

i know elumen is only available in salons, so if i were DIY i'd use topchic...or is elumen really that much better?

any advice appreciated! thanks!