To start with, there is no option of pressing RMB before climbing to the sweeping tentacle. Then, I try to fill in the meter by clicking LMB but I never get to complete this: the meter never fills in time. I have tried to complete the QTE in Easy difficulty and with the Hard QTEs disabled, but still I cannot complete this QTE in time.
Can you help me? I am really enjoying this game (this is the best RPG I have played since the first The Witcher), but this QTE is really getting on my nerves.
Thanks for your help
Edit: Also you can change your keybindings in the Witcher 2 launcher -> options -> input settings. Maybe switching the fast attack to something else for that fight only. I just tried the fight by switching dodge to LMB and fast attack to SPACE, and the QTE changed in Kayran fight accordingly. Since space is the biggest button on your keyboard there should be no problems pressing that with multiple fingers. Altho with this you have to remember that dodge is now in LMB and use that instead of space, which itself can complicate matters even more.