75-250 is indeed a pretty large range. But not too unusual to do that. According to https://www.ysi.com/water-hardness that would be somewhere between soft and slightly hard (no particular endorsement; this was just the first site that I found online). I don't think you'd go horribly wrong by telling your oven to treat this as "medium". Worst case, it prompts you to descale the unit more frequently than strictly necessary. That'll waste a little money on supplies. But if in doubt, that's better than wasting money on repairs. I recommend you buy the descaling tabs in bulk. They regularly show up on Amazon and other online services. And they definitely get cheaper if you buy a bigger package. You'll need two per descale cycle. I usually need to do so every six to nine months. But that might not be the same for you. We use the steam oven very frequently, but we have very soft water. Also, you absolutely want to make sure you have tabs on hand, when the unit needs it. You don't want to find yourself in a situation where you can't use the oven for a few days while waiting for supplies.

I don't know the answer but I am curious. if I were you (and having the benefit of hindsight) I wouldn't hesitate to call any of the Miele USA "Experience Centers" and ask to talk to any of the design staff. If you are in the US start with the Princeton, NJ center, their US headquarters. Even better if you can get to a center. The staff at these centers are a world apart from anyone you'll encounter at any appliance dealer, they use the products for demos and classes and typically have the appliances in their own homes. And it's their job to know the details on what you are asking. And report back and let us know. P.S: A little searching and I found this: https://www.mieleusa.com/media/ex/us/PressReleases/2021/9.2021_Generation_7000_Launch.pdf. Food View sounds interesting. There's also this thread: https://www.houzz.com/discussions/6229141/miele-7000-series-speed-combi-steam#n=10 Advice on calling the experience centers still stands.

I want the broil feature and only those two offer it... wolf does not. Since i will be putting the cso with a single convection under it and another single convection under a cooktop next it I don't think there is an option to mix appliance, While Miele's CSO has a broiler element, it's only about as powerful as what you'd expect for an "average" residential oven. I find it works to give dishes a little bit of heat from the top, but it isn't really very useful for char broiling. That's a problem with a lot of ovens. If you want to get a good broiler, you need to buy a higher-end gas oven (those often advertise what they call "IR" broilers), or you need to buy a Bluestar wall oven. That is one of the few electric ovens that is known for having a very good broiler element. Putting a wall oven under a cooktop doesn't generally work all that well. Not only do you have to negotiate the clearance requirements between the wall oven and the cooktop, there also is the problem that wall ovens typically sit closer to the floor. With in-wall installation, that's awesome. But when you are already in a bottom cabinet, that means the door is too close to the floor and it's very awkward to access. As for mixing and matching, I honestly wouldn't worry too much. Nobody is really going to notice after a few weeks. It's a little more noticeable when the units are directly next to each other. But even that doesn't matter much. We have a stack of Miele CSO and SpeedOven in the wall, and a Bluestar range right next to it. I don't think anybody has spotted the different brands yet. We also have a paneled SubZero fridge, but we installed a Miele handle, as it happened to be cheaper and a design that worked better for us.

Why would a plumbed version be any more of a problem when it breaks than a non-plumbed? Worst case if you replace a plumbed with a non-plumbed then just cap the supply & drain tubes. A non-plumbed has a pump to go bad and that is also the part most likely to fail. Plumbed uses house water pressure in place of the pump so is less likely to need repair to begin with. I can't understand $1500 for the plumbing except huge profit for the plumber & builder. When I added a coffee station in my studio it cost $700 and that was a 60' run for both supply & drain and included plumbing for both a sink and an espresso machine (Breville Touch). Are you sure they didn't say $150?