[ECI-EN] Rendering Intent

Hi all, I have downloaded the new ECI Offset profiles. So my question is which type of rendering intent (Relative Colorimetric or Perceptual) is most suitable with Iso Coated and Iso Webcoated profiles. By the way, I've noticed that while using Relative Colorimetric rendering intent there is a "fall off" of yellow ink in dark tones. (For L=0; a=0; b=0 yellow is 54%, but for L=5; a=0; b=0 yellow is 61%)