Comfort is a very personal thing but I’m also a big fan of ISM saddles on a unicycle 
All credits for the idea goes to @toutestbon
I have three unicycles setup with a combination of a m4o handle saddle bases and different ISM saddles.
You can find more info in this post
I can’t imagine riding them hands-free but you don’t need an aero-bar to appreciate the saddles. I ride in a posture quite similar to what you would do on a city/hybrid bike.
M4O handle saddle base “L” on my KH36 / Nextie carbon rim unicycle:
… and fun fact is that “Adamo” spelled backwards is the name of the company where I have been employed for many years … it must be destiny 