Welcome, have fun here in the forum and with your Kemper Thanks for your introduction...
Sorry, can't help much with the headphones question. I'm using rather old AKG 240s for my studio work and those are nice for guitar via the Kemper as well. But I can not really compare them to others as I typically hear guitar via Kemper on my studio monitors. Potentially some other folks here can comment better on this
P.S.: Nice nickname. Oh, how much I love that piece of Frank Zappa's music