[I feel like I need to parse that one paragraph blob in a word processing app just to decode its content. Only having read it thrice, I'll limit my comments for now to hood construction and general requirements.] In order to obtain relatively equal flow through the filter area, whether baffles or mesh, there has to either be some height above the baffles (probably commensurate with their airfoil length), or similarly above the mesh (narrow dimension), or the mesh has to be so restrictive that it chokes the flow equally at all points (not good). So of all the noted configurations that weren't already rejected by the OP, I would vote for narrowing her consideration to whichever ones provide enough height for the selected filter type and dimensions. Baffles have advantages over mesh filters, but both can filter if the meshes are kept clean. Less tortuous duct paths are preferred over more tortuous paths. Full power actual flow rate (CFM) should be roughly 90 cfm/sq. foot of hood aperture, if possible. A rated capability of the blower of 1.5x that above should accommodate pressure losses in ducting, hood, filters, transitions, and MUA restrictions. Duct area should allow the air velocity in the duct at full power (90 cfm/sq. ft times the aperture area in square feet divided by the duct area in square feet) to be between 1000 and 2000 feet per minute. Aim toward the lower value if all the ducting remains warm in winter, or the higher value if passing through a cold attic. kas

No suggestion other than keep your bend from vertical to horizontal gentle. That is, two 45* bends are better than 1 90* bend.

Renofan, that is Daisy dog in the crate. I'll check over on conversations, it's been so busy around here I haven't had much computer time lately, I'm very sorry I didn't answer before now! Thanks so much for all of the terrific ideas so far! You guys are giving me tons to think about. The body part of the hood is a satin finished stainless, the egdes are mirror finish stainless. As far as age or era of the kitchen, there really isn't one, it's just a collected over time, what makes me happy look. The stove is from 1948, I've had it in storage for over two years waiting for the new kitchen, the hoosier is dated 1939, the beadboard while not original belongs in the house. Our home ( circa 1910) at one point was totally clad in beadboard on the inside, we found all sorts of pieces of it buried in the walls as we've been renovating, this was fairly common in older southern homes. I'm not really going for a era though as much as a feel .. happy, eclectic, cottage, unexpected, a blend of new and old. I know a lot of people like to recreate their kitchen to the time their house was built. I kind of look at it as houses evolve over time, things get replaced and houses aquire a collected over time look.

I think I've got this figured out. First I spoke with the roofing company that put ours on. They recommended against going through the roof if possible. Not because it's terribly difficult, but because it's just generally better to have fewer holes up there. With that many people giving me the same story, I think I'll just go out the wall because it is an option. Then I spoke with the guy I bought the ducting from before. I must have done a poor job explaining what I was trying to do then, or maybe he was getting anxious to get out of there for the upcoming holiday weekend, but he sold me the wrong parts. Instead of the straight boot and 90 degree bend, he should have sold me a torpedo boot which combines the two into one, similar to what you were describing as a potentially custom built piece, John. Then I can use one of the 90 degree bends to jog over a few inches. When they turned in the opposite direction, it's exactly what they do. So I'll be able to avoid the roof, keep everything inside the cabinets and there shouldn't be any custom pieces involved. Perfect.