I've done three of mine over the years. Nothing scientific or by the book. I just guessed them by giving them the same sort of feel and tension as a mattress spring saddle. Ron

email (option): ronpier@talk21.com

I had this problem. I made my saddle according to the measurements Ron gave me.

2 @ 11 ¾" (298mm)
2 @ 13 ¾" (349mm)
2 @15 ¼" (387mm)
1 @ 15 ¾" (400mm)

It's fine for me. I bought the rubber at a sailing shop.

Tomek

email (option): Tomasz-laciak@wp.pl