Addendum @basilisk: re 1200 CFM, I'm not convinced many applications at home need this much? My whole takeaway after reading about the quasi-commercial setups that some here have done (opaone, billy_g, I think a couple others) is that if you have the trio of good capture depth, more containment volume, and active makeup air, you can achieve effective ventilation with lower CFMs.

The counterargument on the other hand for still having a high maximum I think is that an over-specced motor may be able to deliver its lower settings more quietly

But then downside is most control setups with a high maximum don't seem to provide a low enough minimum setting. My 1200 CFM Elica's fixed settings are 375,640,940,1200 on paper and I really would prefer to have a lowest setting that was more like 150 CFM, especially on our heatwave summer days, 375 CFM or whatever I'm actually getting in practice on "low" is quite a lot of humid air pumped into the house by active MUA. I couldn't find Vent-a-hood's specific CFMs-per-speed-setting but I had one distributor say the B200 would be 600 (both fans max), 300 (one fan max), 150 (one fan reduced). I assume their 1200 would therefore be 1200/600/300 for its three settings.

Last note, a couple comments mention Victory and I guess it's cool that they're made in Canada but when I look at the models on their website they appear to have the same standard flaws every other residential hood has: mildly slightly angled baffles that provide little containment volume, not that deep and further wasted depth due to a light bar, etc.

The minimum CFM, after taking into account pressure losses, has to, or at least should, still allow centrifugal extraction of the larger grease particle sizes by the baffles. One may also have a motor design that doesn't run well at very low speeds. DC torque motors driven by electronics synthesizing the correct phases for the motor wiring can go very slow but cost more.

The requirement for full power flow rate is still the same as repeated here ad infinitum. The flow rate after pressure losses has to entrain the plume to enter the baffle slots. It must overcome the tendency for plume momentum to be reversed on surfaces (reflect) and escape the hood (spillage). I have touted an actual 90 ft/min as a good number for maximum cooking plume velocities (potentially up to 1.2 m/s using gas -- Finnish study). With large reservoir volumes below the hood baffles, such as on commercial hoods, there is general averaging at the high baffle area and the plume velocity will have dropped allowing lower hood air velocity and thus lower CFM.

The figure below taken from the Greenheck guide applies to commercial hoods. For residential hoods trying to fit into a residential kitchen, and importantly not having side curtains, I nominally go one column to the right (Greenheck Method row) for cooking content.

Note that "wok" is very high even with commercial hoods, but this is for 100k+ BTUh knee control gas burners, not for more modest capability residential cooktop burners.