To the OP, I have a set of custom molds (made by FutureSonics, for their EM3s), and the Ety ER4P/S phones I had fit the sound holes very snugly, yet I didn't really like the sound. Mainly, because I felt the end of the sound tube on the Etys didn't reach close enough to the end of the insertion part of the sleeve (the part that goes into your ear canal). As a result, I found something seemed missing from the Ety SQ. I also tried using the sleeves with the Atrios and the AL716s, and same result. Both of those phones fit snugly into the sleeve hole, since they are not that different than the Ety tube (the Atrio is a bit thinner).
With my custom sleeves, the end of a phone's sound tube only goes about half-way into the insertion tube. With most of my sleeves (foamies or olives or soft flex), the sound tube is near the end of the sleeve, closer to the ear without any interference. Just my two cents.
The FS custom sleeves are exactly like the ones in the photos. Soft silicone, very comfy, complete seal. But sound??? Just didn't cut it for me, and believe me, I wanted them to work (they cost me $185, with audiologist). Also, the Etys will stick out pretty far, since they are longer than many IEMs (and do not go straight down, as the Atrios do).