My SE-5 generally fit very well. The only way I'm aware of them is if I try to talk to someone and while they're heating up to body temperature - or when I'm specifically concentrating on them - the most felt part is the outer ear being touched at Fossa Triangularis (top front indented part) and right below the top part of Helix (the large ridge), much like you'd put a finger there and touch lightly.
The ear itself feels filled and perhaps I feel like swallowing more often with them in .
Much less annoying than on-ear headphones all in all. These CIEMs are huge, see below for details. (Feel free to ask for pics too.)
They do get somewhat sweaty, but it's not noticeable during use, only when removing them. Was more of an issue during the hot 35+ °C past summer.
(The only other thing I don't like about them is shelved treble - easy to correct with an equalizer.)
Brainwavz B2 with Comply P Slim/trimmed fit nicer, since they don't touch outer ear at all and don't cause the "filled" feel - probably because the foam is softer than silicone.
RE272 was pretty good too while it lasted. However, it is nicer than B2 with silicones, which somewhat feel wrong (scraping?) in the left ear. Much nicer than GR07 with either foam or silicones, where the casing did a number on my outer ear.
What my arbitrarily picked audiologist did wrong (and why I won't go to her again) is press too hard on the impression to remove air bubbles. This distorted the outer ear impression enough to make the end result somewhat tricky to put in properly - have to press on the bottom parts for everything to fully "click" in - the difference is minor in the high end of the response.
Lucky those aren't acrylic. It also took two tries to get a good end result. She could've made them deeper too - they go just 2mm or so past the second bend.
Cleaning ears shouldn't affect the impressions at all unless you really have them clogged. Don't come in for impressions with water in them. Do not use qtips or any other scraping devices - the scraped ear overproduces earwax and changes in shape too.
If you're making them yourself: what you need to make sure of is the depth of and lack of air bubbles. Deeper is always better - the impressions can always be cut down if deemed too long.
Bite block setup is dependent on the CIEM manufacturer. If there aren't any instructions, I'd say "slack jaw" (but closed mouth) impressions without any bite block. If you really need one, pick the narrow side and do not bite hard, just hold it in mouth. Obviously, don't move or talk while the impressions are being taken and are setting.
Edited by AstralStorm - 10/11/12 at 5:14pm