Hi,
It depends. I used mine with the RRS BH40 and that was a bit problematic because the top plate is so wide that the "lever type" lock button collided with the top plate in certain positions. The button is ratcheted so it's not a real problem but a nuisance.
The RRS BH55 works just fine.
Best regards
Erik
I mount my Arca-Swiss Z1/B1 ballheads directly onto both the 3540LS (predecessor of the 3541LS) and the 5540LS (predecessor of the 5541LS). The 5540LS in particular has an extremely broad top-plate. Collision is not a problem since I use L-plates.
In fact, it is the broad-ness of the Series-3 systematic top-plates that allow Gitzo to recommend their usage for upto 500mm Focal length lenses, while the non-systematic Series-3 models like Mountaineer etc are only recommended by Gitzo for Focal lengths upto 300mm (for critical sharpness).
PS: Sorry, read your post once again and you were talking about the lock button and not interference during usage (like when shifting to a portrait mode from a landscape orientation and so on). Yeah that may be a problem with such small ballheads with protruding lever locks.