A little while ago I wrote a short description of the workflow I use with Hugin to combine/enfuse bracketed shots: Only a small testimony - #5 by Carmelo_DrRaw
The good news is that Hugin is available for OSX and works fine (the screenshots in the tutorial are from OSX), so maybe you’ll find it useful…
Concerning the pfbatch command, I forgot you are under OSX… it is not included in the bundle at the moment, but it should be relatively easy to add it.