I've simply used marine boat trailer hub grease and/or teflon on all of the ti interfaces just like I do for my steel frames. Never even think about it. Everything comes apart just fine. Now I haven't used CF parts (just because I don't buy CF parts) so I cannot comment there. I do have ti seatposts with aluminum heads in both of my ti bike. THey have not been given the real test. I don't sweat a lot and I have never seen sweat below my seat and rarely on my stem (except trainer riding when I do not use a towel; not often and not my ti bikes). Writing this last sentence reminds me my good ti bike also has a ti threadless stem on a steel steerer. Again, never been an issue.

Ben