I suppose it would be possible to drill a few small holes in the pipe coming out of the breather box, threading some thin wire through that to make a grid to keep the bronze wool from migrating down. Solder the wires in place to prevent leaks. *Bronze* wool because it is less likely to damage the engines innards than steel wool, should it stray into the wrong place, and *coarse* to prevent crumbling. But if you are concerned about that, just switch the hoses around and add a B18, or equivalent, PCV valve in the hose just above the breather box -- works just as well. BTW the little pipe coming out of the breather box is slightly funnel -shaped to accomodate the rolled up brass flame arrester. This reduces the chances of any bronze wool going down into the breather and, possibly, the crankcase. You might also be able to find some thin brass, copper, or aluminum flashing that you can roll up fairly tight and stuff into that pipe. If you go the PCV valve route, you'll have to make an adapter out of a piece of larger diameter hose that will fit over the breather pipe and the PCV valve - a B18 breather doesn't fit on a B20 block. I'm sure you'll figure out something.
Bob S.