I would consider using Blunt Arrow in between GCD skills for when you aren't saving it to silence something. It's kind of like getting an extra Bloodletter instant to use in between GCD skills every 30 seconds- which is why I usually have the nonmacro version on my crossbar since no one wants to see/hear that every 30 seconds in battle.

Basically instead of Heavy Shot -> 2.5 secs -> Heavy Shot, you'd get Heavy Shot -> 1.25 secs -> Blunt Arrow -> 1.25 secs -> Heavy Shot, so in other words every 30s when it's available you get to use 3 attacks in the same window that you'd otherwise only get to use 2. If you were close to the enemy you could even follow that second Heavy Shot with Repelling Arrow, and then Heavy Shot, meaning instead of just 3 Heavy Shots, you get 3 Heavy Shots, 1 Blunt Arrow, 1 Repelling Shot, in the exact same timeframe.