I too recently purchased SN markers and while surfing the web I stubbled on this chart for SN colors that are compatible with SU colors.
The Decorated Page: Spectrum Noir and Stampin' Up! colours....
and also this site that matches SU, CTMH, Bazzil, ProMarkers & Copics (not Spectrum Noir...Yet)
My Create Ink - ColorMatch ColorLab
I have not tried or tested them out yet. Been busy surfing the Web for tutorials and pinning.
Marker technique, storage... Now I am in search of portable storage for my SN markers