Scroll up and download all my seatrt_on/off.
You cant make it "invisible" anymore. In the past, I used a transparent avatar for seatrt_empty and a gray one for seatrt_join. The client now uses the seatrt_empty for both. I just tried using a transparent image for seatrt_empty, so it would be "invisible" when seated - I was UNABLE TO SIT AT THE TABLE. I cant click it to sit, because it is transparent.
I play on a completely black table (no table shape) and use the same shade black for seatrt_empty and seatrt_off.