@dfkt: in that case, a few more bits that I thought of after writing that down

- If you ever wash the moulds, be sure to dry the canal holes properly (preferably by canned air). The phonak filters 'dies' if they get wet.
- Just something to keep in mind (and it's a possible ongoing problem for me): The PFE's 'nozzles' are short with a recess, unlike the more common 'straight' nozzles of Etys, Shures and Westones. I'm not sure how long the silicone moulds would last if they're frequently taken on and off, because the recessed areas 'digs' into the material overtime. And AFAIK, they can only drill straight holes into these things, so the recesses are not 'accomodated' properly by the design.
- If you can collaborate more with your audiologist, see if you can make the moulds 'custom molded' to the PFE's housing\body as well

Mine is just flat on the outside part, so the PFEs sort of 'hang'.
- I've heard that a bigger diameter of the hole (thru the mold to the IEM) gives better sound quality. This is something you might want to discuss with audiologist. The position, size and shape\direction of the hole for optimum sound transfer (but also need to be balanced for comfort and durability). I'd be very interested to hear his professional opinion and advise on this matter.
Cheers.