Not to minimize, but I think the concerns over carbon monoxide relative to what the hood is doing should be pretty small. The main thing that affects CO production is how the fuel is burning. If there's enough air, as indicated by a solid blue flame, you shouldn't have to worry. And that's set by the air shutters at the various burners. For the hood to affect the amount of air for combustion, it would have to reduce the amount of air that can get into the shutters to mix with the fuel. That isn't going to happen since the air pressure at the burner is always going to be essentially the same as at the air shutter for that burner. For there not to be enough O2 for the fuel (i.e. enough air, but O2 concentration reduced), there's also not going to be enough O2 for you as the cook. That hints at larger problems not related to the range. I'm not saying there aren't houses where makeup air is needed. It's not just to prevent negatively pressurizing the house, it also lets you control where that air is coming from, as opposed to via infiltration (or an open door/window). I vote to get as big a hood as you can- we have a 42" wide by 27" deep VAH over our 36" BS RNB. We also don't necessarily turn it on when cooking unless we need to. Still here despite all that combusted natural gas (i.e. 2H2O + CO2) we've let into the house. Yes, we have a CO monitor, as should everyone.

Hoods that try to mimic actual commercial hoods while retaining a more modest size, practical aspect, and decent aesthetics are widely available from many sources that can be found on the Internet. For example, you can download the Wolf Design Guide and look at the pro island hoods to get an idea. There are others fabricating similar designs. While this is a necessary exercise, the first step is characterizing the parameters of the hood, blower, and make-up air system. To do this, it is necessary to start with the size of the cooktop. If you have already done all the math and know your necessary hood size, then a tour of hood makers' wares is next. Please keep in mind that of performance, aesthetics, and affordability, generally only two out of three can be maximized. Most hoods are compromises within these factors.

I have cooked for up to 100 people and my 4 burner RNB came through with flying colors. But I did learn that I can never have too many ovens when cooking for large parties. They can really help with scaling up your ability to cook. We have the oven in the RNB range and two 24" Miele wall ovens (CSO and SpeedOven). And even that wasn't enough when I make really big meals. I'll end up using the outdoors gas BBQ as another improvised oven, and borrow a commercial warming chest. There are lots of dishes that need to be slow cooked, steamed, or simmered; and all of that works great in the oven. If I had complete freedom in designing my dream kitchen and then later building a house around the kitchen, I might opt for 36" over 30". But I don't think I would go bigger than that. I would absolutely make sure to have at least three ovens though. And if I had to cater frequently, then I'd get two CSO instead of just one. They are so versatile when juggling lots of complex dishes.

Go to good appliance store where they have ranges set up that you can see . Waht is it exactly that you are looking for as to action? I would not think too many people will want to have a stranger check out them cooking. Maybe post what your reservations are about the choice and that could be answered here.