a "spot"? lucky you ... as Carl points out, the only sure way to avoid any oil drips on a stovebolt 6 is to not put any oil in it

there should be a bunch of shredded metal fiber in the breather can as a 'filter' that will trap some of the more liquid part of the condensed fumes - often that 'filter' is gone from folks cleaning it out via
burning [factory recommendation], which will let more of the liquid fraction out, check that for starters, and if the rebuilder didn't clean it, doing so [with solvent] might help for awhile
Bill