David, the original levers were sold by Brownell's but I think they've been discontinued as I've not seen them listed in years. I had a GS friend modify a set of Ruger ring base nuts by welding a steel lever in the screwdriver notch and bluing them. It's actually pretty simple but as I can't weld I needed help. As you can see from the photos below, I reshaped the rear ring lever to clear the bolt release. Off setting it further out would do the same. These are on a Mk. II Magnum, seem OK.
[Linked Image]
[Linked Image]

Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it Almighty God! I know not what course others may take, but as for me, give me liberty of give me death! P. Henry

Deus vult!

Rhodesians all now