RC Model Reviews

I found a YouTube video about setting up throttle mixing for helis, as in throttle goes to rotor pitch an also to a v mix for the engine. But I'm wondering, do people usually mix so that 50% throttle is hovering, or is it usually flat blade pitch?

Not an expert by any stretch, but most seem to advocate hover at slightly more than mid-stick. Whether that is zero degrees pitch will be dependent on your heli, setup and weight (the heli's weight, not yours!).

Not an expert by any stretch, but most seem to advocate hover at slightly more than mid-stick. Whether that is zero degrees pitch will be dependent on your heli, setup and weight (the heli's weight, not yours!). My TREX 550E FBL hovers at just above mid-stick. Maybe 2/3 stick.

It's a matter of choice, preference and application. Probably a bit of history thrown in as well.
While it works perfectly well to set the mid-stick pitch to hover when, it means learning another stick position and fell when converting to +ve/-ve pitch flying as used in aerobatic flying and 3D.
When you go inverted then you'll be wanting as much -ve pitch available as +ve.
Consequently, if you think you're learning curve is heading towards sport, aerobatic or 3D flying then it's best to set your mid-stick pitch to 0°.
Autorotation makes a little more sense when set to 0° also, not that I'm any good at autos

If you're going to flyscale then hover pitch may suit you better.

Another approach is in the thinking involved. If you're set to 0° then you Know what pitch you're applying at a given time +ve or -ve.