How about a Hesston universal from ebay for about $120 with shipping and all...several sellers and each has his/her price. Just go to the ebay site and in their search box put in BS100RD....the RD is for red. If you want black the last 2 letters are BK or BL.
Same size bucket that came on the old MF 35 years ago but is foam/vinyl lined, is low profile, and plenty of dynamic range for the compression springs with adjustment. I have an old seat I took off one of my MF 35's years ago and it didn't have the adjustable suspension springs like this honey! It also fits your watoosie and prevents a lot of side stress on your back from the tractor bouncing back and forth besides the super up and down comfort. Put one on my little 24 hp and it is night and day. Same hole pattern as is on my '60's vintage Fords...2 elongated slots for 2 studs from the tractor.
I have the black universal seats that sell for around $90 with back rest and suspension on my Fords. No way are they as smooth and comfortable as this baby. If I ever replace one of them it will be with a black model of this seat.
Some pics:
This is with the seat flipped up showing the mounting configuration (for 2 studs like my Fords have) and the adjustable spring suspension with plenty of dynamic range for a soft ride, yet room to take a hard bump and not bottom out....picture is in my Branson 2400 compact which needed some serious softening like I assume most compacts......I made the adapter bracket out of some old steel I had to fit the Branson mounting pad.
Couple more shots: