Thanks to Vic Ferrari's awesome playershot scripts...
Last season, with the score tied, Alex Ovechkin and Nicklas Backstrom together were a 54.3% Fenwick duo (link).
With the Capitals trailing, 8-19 were a 66.7% Fenwick (link). Throw in Semin and that becomes 68.1% (link). Have Knuble instead of Semin and it's a 70.7% (link).
Patrick Kane and Jonathan Toews together, with the score tied, were 59.6% (link). They were 68.6% when trailing (link).
Meanwhile, as a team, the Capitals were 59.9% while trailing. The Hawks were 66.8%, and actually right around 59% with the game tied.
I'd wager the Capitals can ramp it up more if they're trailing because a rush-centered offense coupled with a conservative defense by the other team generates lots of shots without allowing many, but with the game tied, the Hawks play a better two-way style. Model yourselves after the Hawks, boys.