Ideal perfect rotations is not something anyone ever really checks unless you're in a super hardcore group that's going for speed kills or Week 1 stuff. If you have a decent GCD uptime, generally line up your party buffs with each two minute burst, and have some semblance of a correct rotation you're probably good. That all should be enough to get FFLogs numbers in the 25-50% range (ie green to blue numbers), which is more than enough for a clear. Hitting something in the slight wrong order, missing a double weave, or using some cooldowns outside of the burst isn't going to torpedo your numbers to the level where it'd matter for hitting enrage or not.
The only time you really run into trouble hitting erange is if multiple people in the group truly don't know how to play and are just terrible at hitting buttons. In my casual group last tier, my co-healer was a constant 0-5% parser because their GCD uptime was just abyssmal and we had two DPS that were just horribly incosistent also hitting gray numbers most of the time. Even then we would clear most fights with some deaths once we got gear. I eventually had to kick those people for social reasons, but it certainly made clears a lot more consistent once we did.
