With tilt and turn windows I can only think of two options, either face mounted shutters to the actual window, which the fabricator might offer, or a rod hung on the face of wall above the window opening, to avoid the window catching on them. A track sheer or drape will work aesthetically, but practically?? Presuming when the windows open, so too would the curtain, it only matters at the end of day when you want to close up and have privacy, so perhaps a holland blind (pull down) so it's least conspicuous.

Hi Neeno, I've seen the use of Zebra ( vision ) ROLLUP blinds with one for each side that will cover down to the lower half window rather than having four blinds and have them fitted to the outside top edge and to the side edges of the pelmets ( window frames.) (If you get to see utube video clips your see what I mean . ) The avantage of doing it that way will allow you to buy only two blinds rather than four . The cost difference between two blinds and extra fabric required to cover the two windows will most likely be cheaper than the extra cost of two extra roll tube mechanism / chains etc etc. when fitted in the recesses of the windows . Also ,due to the bulkeness of blinds , two would no doubt look better than four doing it the way I suggested . Fitting to the timber edges will offer a couple of advantages . One of which will clear the windout handles fitted to the opening widows . Two ,will offer better light reduction from night time lights as the blinds will cover right to frame edges. Three , the design of the Zebra blinds only requires a few inches of the chain movement to close up or open up for vision out or add privacy where normal blockout ROLLUP blinds needs more adjustments and will not offer the same privacy options that the Zebra blinds can offer . Also, if in bed you can open the Zebra blinds slightly by a few inches or roll up just above the top of the lower window ,depending on how much vision and privacy you need and look out of the window whilst still in bed. Being such narrow windows, the small bit of wall between them proberly would not mater if one blind fitted at the top came down over that wall area down to the bottom window. Also you should concider the solar film tinting to offer improved privacy and insulation & fade protection etc for when blinds or even curtains etc are opened up altogether . Although I'm in Tasmania , I have a manufacturer I deal with on the mainland that could arrange sale / installation if required using the Zebra blinds or other types as well contacts for window

http://www.ecostardoubleglazing.com.au/upvc-double-glazed-windows/

Double Hung Windows (aka sash windows) allow you to enjoy the benefits of natural light and air in any context in your home, including areas with limited opening spaces By opening both sashes halfway, of a double-hung window, you allow for more air flow than a single-sliding window. The top sash opening helps hot air to escape. While the lower sash opening draws in cooler, fresh air. Would you install a Double Hung Window over a normal sliding window?