I think the reason you are seeing no response is that no one wants you to race with the original seat. We are now over 20 years wiser. Those fiberglass shells can cause you serious injury. Hopefully all are in landfills somewhere.
I have two 87-89 Reynards currently in my shop. Both with foam/bead seats.
What has been your issue getting a bead seat to work?
I have been using the stock seat with a pad. I'm making a new foam seat as we speak and will not be using the original any longer. I agree with previous comments that it should be scrapped but if you want it contact me.
what do you want for it? got a picture?
Im autox the car and with two driver and a pretty slim chance (one car on course at a time)
of an impact trying to switch bead seat not going to work good. But I tried it with out and move around to much firstname.lastname@example.org