I use 2 headphones and two iems the most.

I use my 660s when I want to just listen and not really focus on the music. Most comfortable pair I own. I use Sundara’s when I really wanna listen and feel the music.

I also love my IE600s. For me, they are almost the perfect IEM. I use them for everything.

When I wanna mix it up I use my FIIO FH7. I love how detailed they are.

The 560s are pretty easy to drive and the K3 would be perfect for this set up.

I own the 200 300 and 600s and the 600s are something special. There one of my favorite IEMs right now and love listening to them over some of my other headphones i have.