Will a Supersplit have any trouble with rounds cut to 18" long

[Whitbread]

If the kinetic type splitters have trouble actually splitting the gnarly ones, from what I've seen, they just cut / slice the wood. Quite amazing.

Yup, same experience here. I sharpened my wedge to the best knife edge I could. When it hits a knot, it just cuts it 9 times out of 10.

My usual cutting is white oak at 23.5" long and up to 26" diameter. The big guys sometimes need flipped and hit again to fully crack in half, but my diesel ss does it just fine. Most of the time is takes 3 people to even try and keep up with it. Had a monster hydraulic a few years back, and I'd never go back now.