In specifically boss fights, pretty sure beamstaff does less damage and overheats way more in the same timespan the burning head cooldown is gone when using wiggle.
Thats the thing tho with the wiggle. You basically can rely on crits with the ridiculous high tick rate that can be achieved. And even when you dont crit, the cooldown reduction that is granted on hitting things anyways still applies to every tick. Which, according to this post is 0.25 seconds every hit.
So, 40 sec cooldown. 30% goes away, thats 28 seconds left.
Lets say beamstaff hits 8 times per second. Which is not unusual from what i have seen. Thats a flat 2 seconds reduction every second. Plus the second that has passed, 3 seconds. Thats the baseline.
Now with crits. Crit on staff, crit on trinket, base crit, getting us to 15%. Leaving pyro passive out on purpose.
Which means every 6th-7th tick is a crit. RSS giving you 2 flat seconds because it still doesnt do what it tooltip suggests.
So take the previous 3 and add 2, thats 5 seconds worth of bar disappearing every 1 second. On average. Against a single target.