Your Viking has a significant amount of power, therefore; you will not want to buy this on a real tight budget. Otherwise, the performance will not be adequate for your needs. Broan makes a liner (RML1048L), power pak (RMPE7004), and an external blower (335) with 1200 CFM or (336) with 1500 CFM. Since you are needing to vent directly to the back, your ducting will have an immediate 90 degree turn towards the wall. In this case, the 1200 CFM blower (335) will work best. This also uses halogen lights, very brilliant. If you are not interested in having a large blower on your outside wall, Broan has another option that could work. Liner RML4548S, power pak RMIP45 and the P8 internal blower. This installs directly into the hood. CFM is on the lower side at 900. Personally, I think you need to be over 1000CFM for your set up. The 1st option up will perform better. Larger blower and a deeper cavity. However, these are just two options from Broan. You may find a different configuration that works better

I hope that's over a 36'' range, otherwise, it's a safety hazard. (Yes, most of the mantle to the counter hoods that you see pictured are actually unsafe to use.) Ventahood does a good quality liner, but nothing in that size range is going to be inexpensive.

Front to back depth should achieve the same capture goal as described for side to side. Sometimes a hood can be mounted farther from the wall and a spacer applied at the back, thereby achieving a somewhat deeper effective hood. Effluent will curl off of a flat back spacer. If flow rate is high enough this effluent will still be captured as it can't escape into the wall. Alternatively, the back spacer can be angled between the back wall and hood entry to reflect upward. Keep in mind as you think about this that the plumes have velocity (more than a meter per second in some cases) and momentum. Momentum is conserved on reflection (accounting for angle of reflection equals angle of incidence relative to the normal, just like light), but overall momentum is degraded by friction with the air and enhanced when entrained in the hood flow. Cooktops and ranges placed against walls with counters on both sides and cabinets above them that drop down below the hood provide a certain degree of flow support as the air is somewhat channeled to the hood and the plumes are somewhat restrained at the sides. Along with an excess of air flow (relative to my suggestion above), you may find that most of the plume is still captured. I have an island configuration so I can only surmise the flow patterns that will likely occur, as informed by various schlieren photographs of commercial hoods that have been published. Hoods can be at any height, but given the plume expansion, have to grow in size the higher they are placed. Commercial hoods often have their apertures at 7 feet above the floor (four feet above the cooking surface), and are built commensurately larger and have appropriately greater air flow (and MUA to replace it). You want the hood to be high enough to avoid head interception, as well as high enough to provide clear sight-lines to the interior of pots. I recommend drawing a side view sketch to scale of the cooking configuration, and add a stick figure cook. Observe sight lines and head vs. hood as the figure bends at the waist. This lends itself to experiments with hood mounting, both in height and offset from the wall. My Wolf pro island hood base is at 34.5 inches above the cooktop for a variety of reasons, and it just clears my head. Hoods that don't extend so far out may still miss one's head due to bending effects. At worst, head interceptions will train the cook to avoid the hood. :) At max power, the zero static pressure flow rate is 1200 CFM. Mounted In the hood, duct, or roof with pressure losses from baffle restrictions, hood transitions, duct losses, and in particular imperfect MUA, the actual flow would likely be closer to 800 CFM. This is higher than the 560 or so nominal flow rate needed for your newly described aperture, so you should have some margin unless the MUA is inadequate, in which case the house pressure will drop some and the flow rate from the blower will match the MUA that results from the MUA design and the pressure the house drops down to. Carbon monoxide sensors become desirable in such cases if there are combustion appliances in use. kas

A couple of links to awesome products that can fit your needs and also be pretty good price compared to similar products in the market: Proline 30' Wall mounted hood - Of course we are going to use our product first- independent of bias though, it is considered to be one of the best hoods of the market and the price is amazing! http://www.prolinerangehoods.com/index.php?main_page=product_info&cPath=32_45&products_id=549 Z-Line - Besides ours, that are good ones on the market like Z-line's. Although it is a small company they are blowing people's minds with an excellent product and good customer service. http://www.zlinekitchen.com/stainless-steel-kn/ Of course, the top-of-the-line company Decor is possibly the best one, but it can be really expansive. http://www.dacor.com/products/collections/modernist/ventilation/30-inch-wall-hood Sincerely, you should just visit different websites and check which ones you feel the most confident about. Hope it was helpful!