I don't understand the problem with the 27-incher. It is only 18 inches high. What is your ceiling height?

I am confident that this hood could vent out the back, although it might need to be modified to do so. From the 2021 Wolf Design Guide, page 156: "For the 24" and 27" deep wall hoods, a horizontal discharge kit is available through an authorized Wolf dealer."

You could, potentially, use an exterior blower which would allow any size up to Wolf's maximum of 1500 CFM rated. The blower you need, however, will be less than that and I'll help (if you don't read other threads) with showing how the containment requirement leads to a blower rating.

Thank you, Kaseki! I just clarified with wolf too that they could do that with a horizontal discharge kit. I would love any help you could offer as we would definitely need a remote blower. We were thinking we would go with wolf for that as well, but do you have any other suggestions? Is there any other range hood you would recommend looking at too?

We could go on forever on manufacturers and their products, almost all of which I haven't owned and won't, as a result, recommend. What is needed before investigating hood system parts is defining what they need to be.

So lets suppose that you have a 36-inch range and a reasonable 42-inch hood over it, set between 30 and 36 inches above it. Assume that the actual capture aperture is 3.5 ft. x 2 ft. (In a wall configuration this might be effectively larger, but that doesn't apply to this bit of analysis, which actually deals with presumed ratios between baffle gap areas and capture area, and is highly approximate and influenced by plume velocities.)

It is desirable for residential baffle hoods such as Wolf makes that the intake air flow velocity be somewhere in the ball park of 90 ft/min. With an aperture of 7 sq. ft. (see above) you would want an actual flow volume rate of 630 CFM.

Depending on your make-up air system, which somewhat depends on your combustion appliances, if any, you will need a blower with a zero static pressure rating higher than 630 CFM by a factor determined by MUA achieved house pressure match to outside, and by pressure loss in the baffles, which varies with flow rate. Your short duct pressure loss will be minimal.

So, consider the Broan-NuTone 900 CFM external blower that I have a fan curve for that Wolf sent me in 2008. At 630 CFM, the pressure loss of the hood is shown as 0.4 inches of water column. The total pressure loss capability at this flow rate is 0.85 in., w.c. This leaves 0.45 available to the MUA. In there are no combustion appliances, this limit can be avoided by a damper controlled duct and any 3M Filtrite 1-inch furnace filter. However, a tighter inside-outside pressure drop may be desirable to assure little air infiltration through walls. If there are combustion appliances such as gas water heaters that require very small differential pressures to not back-draft carbon monoxide, then they drive the degree of tighter control.

Before getting too fancy, what combustion appliances do you have, excluding the range?