I do colored wings all the time - My Siahi is almost gone and I've got BUs galore of Dark Diversion - so I'm already partial. BI is dark enough to do a cats eye but also smooth enough to just do it blended smokily all around the eye or use it as a base or all over the lid. People should always check makeup out in person anyways, though….I think it will look beautiful on you.
Copperthorne is the fussy one for sure. BI is seriously unique for a gel liner, and honestly, I've seen very few pencils out there that can come close to the rich deep velvety effect it has. There's certainly going to be so much coming out in the fall that saving where you can is a good idea - that's for sure. I try to be more of an anti-enabler around here, but BI is for sure one of the best products MAC's put out all year.