You know, I've never quite understood why loading a Barnack is such a problem. True, it is definitely possible to insert film and take up spool in such a way that the film will not advance properly, but that should be perfectly clear by the way that the film canister is seated in the camera. If it doesn't clearly and solidly slide all the way down into position there will be a springy feeling to the canister when you press on it. Simply take both the take up spool and canister out, make sure that the film is in a straight line between canister and take up spool, and reinsert. Shouldn't take more that a couple of tries to get it right. Of course, the card trick makes the whole exercise a no-brainer, and would probably save a lot of time and trouble if done routinely.
Cheers...
Rem