The first step was to get the seat and cover off, because they are heavy and unwieldy. So, initially, I had to unscrew eight hinges (four on each side--two on the cover and two on the seat). Some of the screws were extremely tight, and I had to use several different size screwdrivers, hoping that I would not completely strip the screws. The last screw did become stripped, so I used a large flathead screwdriver to try and force it out of the seat. That last hinge snapped, and a piece flew into the toilet. I would have to fish it out, but at least I could finally remove the seat.
The bolts were a nightmare to get out. There is no mechanism on the nut assembly to untighten it. To make matters worse, my toilet is in a nook with very little space along the sides of the toilet.
On one side, the side with the most space, I took pliers and held the nut piece in place with pliers. Then by holding on as tightly as I could to the flexing, multi-piece hinge, I finally unscrewed the nut combination from below. I had to stretch out on the floor, with my head past the edge of the toilet. Unscrewing took a very long time. The pliers could only do very small turns because the recess where it was located was very small. But once I got the long nut piece unscrewed, I could lift out the bolt.
On the other side, where there was less clearance, I got a mirror to try and see if I could manipulate the nut. There was not enough room to stretch out and be able to get my hand/arm in place. So I figured that my only option was to try and get the hinge off first. Adding to the difficulty was the fact that the four hinge pieces kept flapping against the porcelain (I was concerned about scratches). I did finally manage to unscrew it. But then I was left with the situation that even though the bolt had no head, everything was way too long to slip out from the bottom.
I tried to use a hacksaw to take off the excess, but didn't make much headway other than making a few gouges. I couldn't find anything that would cut into the hard nylon or plastic nut assembly, so that route was out. I spent several hours agonizing over what to do, searching the internet, and trying to come up with a way to deal with the head of the bolt. At once point, I thought I might have to go out and purchase a bolt cutter (the heavier-duty ones aren't cheap). But finally, I decided to try angling out the bolt from the bottom, pulling the nut assembly as far away from the hole as possible. Probably because of the gouges in the top of the bolt, there was just enough clearance to slip it out.
Perhaps I didn't have the right blade on my hacksaw. I had also tried a jig saw. I had a dremel, but not a metal cutting blade--the closest place to purchase one was 30 miles away. But I feel strongly that the manufacturer should have given instructions in the manual for how to remove this toilet seat, rather than leaving it up to the customer to try and figure it out on their own. If there are tools you have to have, it would be way better to know this in advance. Perhaps this seat is so difficult to remove that any instruction was a deliberate omission.