Update. All I have left is the custom seat base. Should work for any AL seat. $100. If you are shopping for a halo seat, I would go AL. Many of the good ones allow mixing and matching of different seat and back widths and heights, and many are adjustable after purchase.
Don’t get a cheap AL seat tho. Those are marketed for the circle track crowd and they aren’t rigid enough for road racing.
Kirkey 70160 halo seat with custom steel mount for sale. Great condition. No visible wear. The mount bolts right to the OEM seat fastening points. $500. No shipping. Will have to come to you via the track buddy system. I’m in SE region. Should be easy enough to get the seat to MidS, Great Lakes, MidAtl, and Florida regions.
$400 for the seat, $100 for the base.
Kirkey makes this seat design in 14, 15, 16, and 17" widths. This is the 16. I’ve a 31" waist and the seatbase is a bit too roomy for me.
One of the charms of an Aluminum seat is that many designs are adjustable. This seat is adjustable for torso height, which means you can set the halo at a height that allows your beady little eyes to peer over the padded bar, hence peripheral vision.