Reviving an old thread:
A couple of months ago I was on the verge of abandoning my se535's alltogether.
The medium black foam olives by far had the best isolation, but the deepest bass lacked a bit and high frequencies were the weakest of all the tips. I also got sore ears using them. I could not get the small olives to seal in my ears.
The yellow foamies had the weakest bass of all the tips I could get a seal with. And they didn't last very long.
The grey flex tips had good bass and more treble, but the midrange and treble seemed a bit uneven and they did not stay very well in my ears when moving my head.
The triple flanges were downright painful and I had trouble getting a good seal. Even when shortening the stem.
Then I read on this forum that cutting off the smallest flange on the triple flanges might do the trick. I did so and after trimming the stem a tiny bit at a time until I could both make the tip seal securely and have the body of the earphone flush against the opening of my ear canal my problems are over. The fit felt a bit tight for the first few days, but the isolation is equal to the black olives, the bass is deep and tight, the midrange is the best I have had from these iems and the high frequencies are the most present, extended and smooth of all the tips I have tried. I would still like a bit more high frequency presence and sparkle, but that is just my preference - YMMV.
After about a week of normal use, the tips sort of customized themselves to the shape of my ear canals and they are now very comfortable, secure fitting and strange looking .
Hope this can be helpful.