New GH5 Owner! A few questions I'd like to answer before an upcoming shoot.

Very thrilled to have this camera in my hands. Have been shooting some test footage in my spare time but I have a few questions for you all.

1920x1080 59.94 (33% slow effect at 180fps VFR) vs 1920x1080 23.98 (13% slow effect at 180fps VFR). Any advantage of shooting one over the other in regard to slomo capabilities or in general. Still trying to wrap my head around VFR. I'm importing everything into a 23.98 timeline.

sec/iso 320 vs 400 when shooting at 180fps VFR. The correct amount would be 360 but that doesn't seem to be an option, so would it be better to shoot slightly higher or slower?

Using wave. Seemed to be a "pro-level" selling point on the camera. But it covers over a quarter of the screen. Is there a way to shrink the size, and if not, how are you guys going about making the most of this feature if at all.

Manual Focusing. So as well all know there's no auto-focus once you're shooting above a certain fps. A large amount of my test footage is coming out blurry as I'm having difficulty with manual focus. I have peaking turned on and the magnification feature, but peaking doesn't seem to be showing up no matter how I focus it on a large number of my shots. Any suggestions? Could I be shooting in the wrong aperture or?

Thanks in advance, excited to be apart of this community.