please note that i have all of them saved to get back to rate except taku route one so i my memory might not exactly be serving me right
taku route: 9/10. the only bad thing about it is all of the screen being black but i think it's okay considering almost all of the vomit scenes are like that. the drug part and his vision going bad, and also the whole situation is perfect and the sound effects were pretty good as far as i remember.
fujieda route
first one when he receives the package: 8/10. very nice sound effects, lots of gagging sounds, you can hear towa is having hard time breathing, the situation is nice as well.
second one: 7/10. wonderful that he's moaning in pain this time, also him almost passing out and fujieda dashing there is a bonus point. however despite his cute moans and hoarse voice, it has no gagging sounds and the sound effects are relatively short.
third one: 4/10. obviously cute but all you hear is the sound effect of it going down the toilet, one point bonus for towa's sigh at the end.
the red room one: 8/10. sound effect falls a bit flat but the situation is perfect, lots of gagging and hard breathing, probably the longest gag sounds among all of the vomiting scenes. + barely holding back himself from puking again after fujieda ask him if he's okay again.

for some reason i felt like there were more scenes lol.