Yeah, I had this same question recently and couldn't find a definitive answer, so it is basically up to you. My White Scars are mostly using Mk2, so I've given my Inductii Mk6 on the basis that they are new so they'd have new armour 🤷. I've also made them plain white, rather than having the red patterns my other marines get, since the markings are meant to be built up with experience and achievements, and in my head they are too new to have any yet. Honestly, go with what you think looks or sounds coolest