Commercial hoods are typically mounted so the bottom is at seven feet from the floor. The only requirement is to have enough flow for the necessarily larger hood needed for capture at the increased height.

A six by four foot hood aperture is certainly big enough, but it begs for a lot of air flow. And this hood has a cut-away front reducing capture volume so one doesn't want to let the rising plume loiter about in the hood. I would suggest a flow rate maximum of 90 cfm/sq. ft. of aperture, or 2160 CFM in this case, and the zero static pressure blower rating should be higher due to the pressure drop in the ducting and baffles. This should handle your range and future salamander.

MUA restriction can call for more. You are definitely in the commercial system regime with that large of a hood. You are embracing the world of 12-inch or larger ducting, and an upblast roof or wall exhaust blower.

Even if you choose to live with 50 CFM/sq.ft. per the Greenheck guide [see other thread], you have 24 x 50 x 1.5 = 1800 rated CFM as a likely required blower spec. You will also need an actual 1200 CFM of MUA, which may itself require an 1800 CFM rated blower, or a very large large, low restriction path for the MUA. Even if the MUA path has no air filtering or heater restriction, the diffuser at the kitchen will have to be large to have low loss. Alternatively, open all windows. The screens alone will likely have a pressure drop that brings the MUA pressure loss to the range where the 1.5X factor accounts for it.

You might consider only three feet of projection instead of four feet to save a lot of air flow. That overhang should be enough for any likely plume expansion from range front to edge of the capture area, unless you expect a fair amount of cross drafts disturbing the rising plumes.

I think if you can fit it all, you can have a really great kitchen ventilation system, but it may be most practical to get Greenheck or equivalent involved in the planning and execution.