I know the Shure tri-flanges would be more suitable as they would definitely fit, but for the price they are asking, I'm going to go for the Ety 5-packs instead - especially as I will be cutting them down to bi-flanges as many on this forum have suggested.
Thanks for any help regarding this somewhat puzzling question...
You can use the Ety triflanges but there's no guarantee of fit. The Shure triflanged ship with really long 'stalks, whereas the Ety tips ship with no stalk left. For some ears with the E5c, you need a bit of stalk.
Imo, the Ety triple flanges are a bad match for both the Ety-ER4p/S and Shure E3. High frequency resonances, sibilance, etc.
I use the E3's soft flex sleeves with the Etys. With some major bass and lower midrange boost from my old Sony D-465, the Etys don't too bad actually, better than the E3. The foam tips sound ok, too, but are too uncomfortable and too much of a hassle to get into my ears quickly. The Shure's soft flex sleeves are the best by a wide margin due to good sound quality and comfort combined. The Etys are quite capable canalphones in terms of headstage, resolution, treble extension, etc. but the sleeves that come with them make them either sound bad or too uncomfortable to wear.