...but I can't find anyone selling them except B&H, on special order basis (so non-returnable), so I'm a little reluctant.
B&H is a fulfillment vendor offering many products they're not actual dealers for. They don't stock them. You order, they take your money and they then drop-ship or re-ship after the manufacturer or importer delivers the product to them.
With all the good Chinese knock-offs (Induro, Benro, Sunway etc.) of Arca Swiss style heads, rails and clamps why would you buy a product with no warranty and no option to return it ?