In scanning this thread I'm reliving the same issues I had with my UE SF5Pros having narrow ear canals also. In the long run, I found that Comply tips had the best comfort but killed the highs. I also ended up doing the flip-flop mod (swap the left and right connections to the IEMs and wear the with the logo facing into the ear) to get a better fit. More recently, I've been sticking with the smallest stock silicone tip (having gone through double flanges, foamies, complys put on backwards, etc) but found that they didn't isolate outside noise the best - with the result that detail was a bit lost and bass attenuated a bit.
Last night, I was playing with a DIY hybrid - trying to get the best of both comply and silicone tip worlds (better isolarion and deeper bass extension from the comply but retaining the crisp highs from the silicone tips) but then my aging SF5Pros fell apart. :(
Basically though, if you de-core a pair of small size comply tip, cut-off about 1/4" of the back end of the decored foams, you can take the result and recore the foams onto the silicone tips. Initially, I tried this with the full foam (not cut) but found that this put too much pressure on my ear canals making them uncomfortable. I was impressed though with the depth of bass and better details that I was hearing with this setup.
I didn't get a chance to listen much to the setup with the trimmed foam but initially it seemed more comfortable and retained the bass and detail I noticed before. I could only give it a couple of minutes of listening so that of course is not enough time for a comfort test, Sadly, that was when the casing on one of the moniters fell apart at the point where the cable connects to it and unfortunatly the wires got torn also so I can't glue em together again.
Anyone know of a use for what's left? My brain says chuck-em but my rat-pack heart says there's some use for em. (: