If the range surface is at 36 inches, which is normal, and the hood 36 inches higher, which is reasonable, then the hood is at 72 inches (6 ft) above the floor. That is higher than 5'10" (70 inches), without even counting the effect of bending at the waist. So head banging would depend on shoe construction.

Because cooking effluent plumes expand as they rise, the 27-inch depth (front-to-back) will have better capture.

Depending on various factors, such as side cabinets, your hood width would provide better side capture if greater than 48 inches, e.g., 54 inches, for good capture of plumes from pans on burners closest to the range sides.

You need to address duct size, length, and make-up air configuration to determine the excess in blower rating to provide the needed full-power flow rate. I recommend approximately 90 ft/min air velocity at the hood aperture, which for a 48 x 24 = 8 sq. ft. aperture (assuming a light bar but you can recalculate for actual dimensions) means 720 CFM actual flow, which may require 1000 or more CFM blower rating to achieve the desired actual flow rate given pressure losses (cooktop to outside and back to cooktop). Blower flow rates are reduced by loop pressure losses.

Do not put off the make-up air (MUA) supply portion of your project until later; it is integral to the ventilation portion. It is also necessary for adequate flow and in some residential household configurations for safety. It may be enforced by municipal authorities.

Review of the many hood and MUA threads here will provide additional insights.

I’d get the 24” deep one. While the 27” deep one will have more capture area front-to-back, I think 24” still covers the front burners and is sufficient. I’d worry that the 27” one will be too intrusive into the kitchen. What you could do is get 2 pieces of cardboard - from opened-up shipping boxes would be good. One would be cut to 48”x24”, and one would be cut to 48”x27”. Hold them up where the hood will go. If you feel that the 27” deep one is fine, then get that.

Although it sounds like you've made up your minds, why Vent a Hood? I am somewhat fixated on this, but my experience with our VAH is that it's expensive, extremely and annoyingly loud, a huge PITA to clean, and a major underperformer. You can do so much better with a baffled hood, and it in turn opens up options like using an external remote blower, which enormously reduces noise levels while improving performance.

We have a 27" deep Ventahood installed ~35" over a BlueStar range and really appreciate the extra depth. The hood's switches and lighting eat up about 3" of depth, so the capture space pretty much begins directly above the front edge of the burners.

FWIW, I'm 6' and the hood is not an obstacle for me. And purely aesthetically, we went with their "biscuit" finish, which is less expensive than stainless and proved to be an almost perfect match for our upper cabinets.

@mumkin May I ask you, if you're 6' and your 27" deep ventahood doesn't bother you (hit your head while using), how far from the countertop is it?

I'm also 6' and I'm highly considering the same setup as you - 27" deep hood, 42" long over a 36" range.

I almost feel as if the vent is closer to the counter, say 28-30" or so, making it land closer to my forehead rather than the top of my head, say 36-38" or so, I'm less likely to "bump" into it. I'd rather see something in front of me and know how far it protrudes and adjust my stance accordingly, than to have something looming above me out of my line of sight, where the slightest spring in my step causes the top of my head to get whacked. LOL

Curious to know how you set this up! Thank you!

Mark, the lower edge of my hood is 34 5/8” above the counter, and 33 3/8” above the stove top. At my height (6’), if I’m literally pressed up against the oven door and lean forward, the hood hits my hairline, but if i am not absolutely frotteurizing it, i can kow-tow with impunity. I‘ve never hit my head on it when cooking. Maybe one or twice when cleaning the hood, but that involves perching on the burners, leaning backward and contorting—not a use case one can really optimize for

@mumkin thank you so much for sharing, as well as the photo. Your setup looks great and very clean. Love the counters too!