Free hit of soul you can get after defeating Marmu, loses no time assuming you have wielder on and are dream gating out after the essence. In TE it lets you skip the soul totem before Traitor Lord which saves 0.7, but probably useful in other categories like 112. The petra isn't there 100% of the time but it is still very worth it on average to go for.
Consistent 2 shriek marmu kill. Dream nail at the right side of the bush, hold right and shriek asap, stop holding right and jump shriek. Important to not jump too high, else marmu will hit you often. I tend to just cancel my jump by using shriek. How far right you get is more lenient than the height. Just make sure you are at least at the right side of the bush
Here is all the boss battles in 112 and 107 where flukenest has been found to be either optimal or viable/ preferable over the non flukes alternative. I will first post the unambiguously optimal fights and then post the ones which may come to preference.
Nosk: Good RNG fight saves 10 seconds over non flukes combsob. Bad rng isn't super punishing as nosk has a lot of attacks where he can get multihit, you shouldn't be losing more than 5 seconds. If he goes into the ceiling instantly you can shriek as usual.
The charm loadout is: Shaman stone, spell twister and flukenest, needs overcharming.
Collector: There is a completely consistent quickkill which has been posted in strats before. Additionally, flukes will instakill collector out of the final phase. In total this is seven seconds of timesave over perfect shriek only fight.
Charm loadout is shaman stone, flukenest and dreamwielder. Charm switch optimally at tram bench or at oro bench for a safety heal.
Watcher Knights: Saves 5 seconds on average over optimal shriek fight. Each watcher dies in three fluke casts, so you can kill them before they even attack. To make up for the lack of twister i have come up with a couple of strats to gather soul (showcased in video). Its still optimal to throw the chandelier down, and the fight needs to be started with full soul.