As my experience goes, the darker ones are older. I bought a pair with a 1935 gymnasterka some years ago and it was very, very dark... looked like black. You could only realize it was blue when you set it against actual black cloth. At the time I thought they were not army issue but some civil ministry or railway police. Later I found out they were good.
If you look at the pic, those in kersey blue look like breeches and not sharovari (fifties issue?).
I only have one pair dated, an other ranks (without piping) example dated 1941 (it costed me very, very cheap because it had some moth holes, so I don't doubt about the authenticity of the markings). These are plain navy blue, like number 2 from the right.
Parad officer breeche to me
I think all those are parade / everyday trousers. I Think that breeches (low waistband with belt-loops) are either more modern (you seldom see sharovari dated after the mid- late fifties), either they were made for more formal occassions on more temperate weather (they tend to be less hot). Both examples coexist during the mid forties / mid fifties, then sharovari giving way to breeches (with the hips cut like long trousers) specially after the 1956-8 regulations that ushered in a more modern uniform in cut for officers.
Regulations are always very ambigous. They state only them to be <<of dark blue cloth>>. But it is true that if you look at the post war regulations the drawings show more a <<royal blue>> shade than navy blue.
There are also two words: Sharovari and bridzhi. Sharovari comes from the Arab word for the Turkish loose trousers (Seroual in French). If you look to civilian examples (vintage or modern reproductions that you can find in most tourist shops in North Africa) or to French or Spanish colonial examples you will see they aleays retain this high waistband with the reinforcing thread.