I don't see the benefit of Tx series unless you produce enough liquid earwax to litteraly "flood" the IEMs.
If you trim the foam and the IEM nozzles come very close to the foam surface, you could dirty the nozzle though...
I had such an issue only once, with proprietary silicon tips which were only 1mm longer then the IEM nozzle they came with.
Never happened with Comply T or Ts series (currently using 100, 400 and 500 bore sizes).
BTW, I'm also a strong believer in the Ts series, it is more "universal" with one size only and seems to fit almost all ear shape (except very small ear canals).
T/Tx are bad at taking turns in the ear canal, while the Ts spherical shape will allow different orientations (think of it as a ball joint which can rotate easily).
Edited by tienbasse - 1/22/12 at 4:00am