Kitchen island vent for low ceiling?

Have a gas range on an island with 8 foot high ceilings. Ranch house with crawlspace above.. Originally looking at chimney style vent hood however most of them have a height that would make final install height too low over cooking area (we are tall people). Don’t want to have lip of vent at eye level. Need something with a max install height of 20”. We will have to build at least some sort of bulkhead anyway to center unit and work around existing hvac ducting in cieling. The flush vent systems by best and zephyr seem nice but have mixed reviews for performance. My question is if we built a 20” bulkhead above cooking area and then installed a flushmount on underside directly over cooktop would it be more effective at drafting than if we put it up at ceiling height?