OK, let's clarify things up here:
Drain Rate: Affects Taiko. A higher drain rate means a higher HP reduction when a note is missed. Generally though no one really minds that. Plus, the HP system on osu!Taiko isn't really much authentic.
Circle Size: Does not affect Taiko at all. I always set this to smallest whenever I'm making a Taiko-only map lol
Overall Difficulty: orzviously. Affects hitframe strictness.
Slider Tick: Does not affect Taiko at all. osu! predetermines the drumrolls' ticks depending on the BPM of the song.
Drain Rate: Affects Taiko. A higher drain rate means a higher HP reduction when a note is missed. Generally though no one really minds that. Plus, the HP system on osu!Taiko isn't really much authentic.
Circle Size: Does not affect Taiko at all. I always set this to smallest whenever I'm making a Taiko-only map lol
Overall Difficulty: orzviously. Affects hitframe strictness.
Slider Tick: Does not affect Taiko at all. osu! predetermines the drumrolls' ticks depending on the BPM of the song.