1901 get 1100 loyalty points as the default, rather than the 1000 that standard ST holders get. That gives you some level of "priority" over all away games that are limited by loyalty points, depending on where the cut off between the LP bands actually lies.
Std ST holders get 1000 LP; 1901 get 1100. No other benefits for away game tix currently.
Can't be that high. 35% of 1901 = 1000 people - that's more than the entire away following at some games last season! My guess would have been 10%, which is a higher proportion than of the standard ST...