Replacement driver shaft?
In the event your looking at a Diamana B50 R-flex,
Wishon profiling software shows a UST Competition 75 A-Flex would be close as would a Graphite Design YS-6+ in R-Flex
older shafts but good ones. The UST might be tough to the find, but the Graphite Design should be readily available for around $50 bucks these days.