I have not bothered. When I used an R&D I used flat braided copper wire filled with solder at each end and then drilled for the coupling bolts. This worked quite well for a couple of seasons, but the flex eventually broke it down. I was never convinced it was necessary as my prop has a whopping anode on the end and the external anode erodes evenly. So did not bother making new ones when I fitted the Bullflex. Everything still seems Ok 5 years on.
The method would work, however and definitely better than a single wire.