I replaced the seat with Lowe's or Home Depot seats. Never had a problem. I removed the seat from the toilet and traced it on a sheet of butcher block paper (actually, packing wrapping paper), cut it out, folded it up and put it in my pocket. I then went to Lowe's and simply held my template up to the existing seats hanging on the wall for display. I found the one that matched almost perfect. I checked the holes where it mounts to the toilet and they matched also.
A year later, we added the Bidet.