The state of your Bandit's Guile isn't as important as some of you make it out to be. Rupture does more damage per energy than one Eviscerate whether it's at 0%, 10%, 20% or 30%. Unless you are actively saving up 5 anticipation charges to delay finishers which I somehow doubt hardly anyone does you should simply apply Rupture the moment it drops off. Also reapplying before the final tick doesn't impact or change your DPS in any way shape or form. The tick still goes off with the damage and insight level it was applied.
If you don't have Rupture ticking on your target, you aren't cleaving with Blade Flurry and the full duration of Rupture will tick, apply Rupture. If you used Eviscerate on accident or couldn't Rupture for some reason, oh well no big deal. But weaving in Ruptures regardless of your state of procs and buffs will increase your DPS a slight amount.