"Texture blocked"? Ooooh, that sounds painful. Drink plenty of fluids and add more fiber to your diet.
I'm not sure exactly when these stations were in service, but the general style suggests mid pre-TOS (around 2225), say around when the Valley Forges were introduced? The large internal docks were too small for Constitutions (they just barely squeeze in), so the largest station was probably designed for smaller, earlier ships. I suppose they could be seen with Lancasters, Valley Forges, etc. They look a bit too new for Moskvas, though.
I'd rather be designing ships, but have some blockage issues of my own to deal with.
By the way, the size of the K7 was determined by the spacing of windows on this schematic. I matched two row of window to the primary hull disk of Enterprise.
http://www.ex-astris-scientia.org/schematics/k7.jpg Bernd's estimate of 450 m diameter is fairly close to what I get.