We have triple paned tilt-turn windows from Germany. My comment is that if you split the window in two and both sides are operational, that window will be very heavy. It is not a problem for the tilt position, but if you swing it open, when you swing it closed you may need to lift it slightly in order for it to close properly. I am basing this on the windows we have that have openings about that size. I like WoW's idea of a 25:50:25 window.

You will have to re-stucco the house with new construction windows.

@Windows on Washington Ltd and @quasiexpert Sorry if my last message came through in a different tone, I'd been up for awhile and was just stream of consciousness posting. From my research here on this forum, it just seems that invariably quite a few posts discount the entry level windows and recommend the Anderson 400 or Marvin Integrity ++ type windows. Hoping that I can learn from you all. Our situation is a new construction in the deep South (Birmingham AL). About 60 windows on the house. Front facing windows I believe have to be aluminum clad, the rear might be able to get way with a vinyl window. Rear will be facing the South West, but looks like there will be some tree coverage as well as decks/roofing for the majority of the windows. The builder has spec'd Piva Group vinyl windows. They are Argon filled, double glazed, Low E 366. U-factor 0.26, SHGC 0.21, Visible Transmittance 0.49 and air leakage < 0.3. He mentioned that the Anderson 100's might be within the same price range, and we would be interested in the Smart Sun if it's available with the low E4 coating to help protect the wood floors. While I can appreciate the beauty of the wood interiors, our preference is for something low maintenance and can handle sun without fading. We've never had a double hung window before and a single hung is fine. We open the windows in our current house maybe 8-10 times a year to air the house out, otherwise they stay shut. Sadly, we wash our windows even less times /duck Given the above criteria, might you have some thoughts or recommendations, or are there any additional questions I might answer?

Here in the USA, people expect a framed closet and direct bathroom access for every bedroom, something that is totally unusual in Austria. I am not sure where this comment comes from. Sure, a framed closet is more or less expected, but not necessarily a walk in closet and the direct bathroom access is certainly not what most home owner expects. In my middle to upper middle class community in Central Mass, nobody expects a direct bathroom access for every bathroom. It is expected for the master, but other rooms have access to the hall bathroom. This said, the lack of windows would bother me and I would try to change the plan so that I have one. And if the OP can afford expensive cars, he can probably also afford security mechanisms.