To come back to that old thread,
Better than buying another mattebox, I just did cut some long carbon rodes in to two small one.
Here is a pic with a 50mm Summicron and three stages.
As you can see the larger part of the RR MatteBox doesn't touch the rode and can now be adjust up or down with no problem.
Works also with the 28mm Elmarit or the 50mm Nikon F1.4
The irony is, I first bought the shortest RedRock carbon rodes possible, they were too long with such small lenses.
Weird RedRock doesn't propose shorter ones.
Glad I dindn't bought another chunk of metal.