This is my current configuration:
Earside felt removed, fatmat + paxmate baffle, shure 840 pad + cotton, baffle port sealed, bass vent sealed except 3mm
Mass load baffle, stock white felt under some type of felt that i can find
This is the clay i use, dont' know if it's good enough, that's the simple clay that the kid using around
Paxmate cup floor with some cardboard
Cotton stuff inside the cup.
This config have quite good mid, treble and soundstage for a closed can but it doesn't go very low in bass section, using test tone, 30hz is quite weak, 20hz is nearly unaudible and bass impact is weak too. I need some suggestion!