I have the Bride Zeta III Type L for my big arse also. It gives a lot more support than the stock seat and also the reclinable seats.
I'm running off a Mugen seat bracket because the Bride bracket was higher than the Mugen, so then it made my thigh rub on the steering wheel.
I also have the Ergo I on my passenger seat. I had the Ergo before, but after I started tracking, I wanted a seat with more support. I tried the Mugens. They were pretty small, I did fit, but once I wore jeans and a jacket, I was squished in the seat.
Now for reference, I'm 6'1", 36 waist and I weigh 230lbs. (I KNOW I KNOW, I need to lose some weight)
I also tried the Spoon seat, the butt support is smaller, so then you sort of sink in more with the seat. Also the padding is limited, you're basically sitting on carbon. But with the price being double the Bride, I chose the Bride instead.
I'll get more pics of my seats later, we also have a Spoon seat in AJ PwR's car and a Mugen one.