Some birds can have more prominent inner primary windows but the inner webs of the outer primaries are darker and less contrasting than those of Vega.
Lighting plays a big part but the underside of the outer and mid-primaries tend to be much darker than Vega.
Because of the variation in all gulls it may seem pointless to include a small number of selected examples for comparison but these Vega spread wing shots give a general idea of how the window and outer primaries look at this time of year when they're looking rather faded. Particularly the very pale primary window and more contrast between inner and outer webs of the outer primaries.
Vega primaries in late March / early April
The underside of the outer primaries tend to be lighter in Vega but light conditions play a big part; those of Taimyr can look quite whitish at times but prolonged views will give a more accurate impression.
The following Taimyr Gulls are mostly different birds and hint at the range of grey-saddled type variation.
The black in the tail band narrows towards t6 but most don't show as much white on the closed tail as this bird.
In the background of the previous gull, this was one of relatively few fresh-looking heavily marked birds still around.
I'm guessing the prominent row of barred upper scapulars on the rear bird were early-moulted feathers.