Due to River of Blood, it's not really viable to stance dance for a no-oGCD Heavy Shot string in the same way that Machinists might. It's really best to just have WM on 99% of the time. The 1% is comprised of:

A) Situations where you are going to be losing a substantial (say, more than 1 in 5) amount of GCDs due to either extended movement or single-target enemy deaths. These don't really happen in Alex Savage, but Bis EX wind phase can be an example of the former, and Rav EX butterflies arguably of the latter.

B) Extremely rare cases where you know exactly when your auto-attacks are happening and have a specific plan to spend ~3.25 or ~6.5 seconds outside of WM because some confluence of factors causes it to be an overall potency gain. It is not recommended for anyone to consider this unless they are very comfortable with the class and have done the math to be certain that it isn't just dumb.