It's a "chose your poison" situation. Felt, even in thinnest form I could find, while removing that aggressive bite at the top, does steal some details and narrows soundstage.
I don't feel that making partial rings is a good idea as it creates uneven reflection surface which could wreak havoc in the whole sound reproduction, could be wrong though.
Felt might be just too much as a dampening material in T1 situation, I will be playing with self adhesive creatology foam, the stuff that was successfully used in HD800 Anax mod, will post results later.
Just had creatology foam installed, I've used full circles.
So far seems like this material creates the most subtle effect, smoothen treble spikes a smidge but do not affect soundstage or take air out. I wouldn't bet on that but it feels like details are actually better with the mod, guess some ringing was masking them before.
Definitely like what I hear so far.