To answer your first question, I almost always use comma delimited regexes, in that way it's second nature for me to write eminently (IMO) readable regex's manipulating strings containing slashes (/) ... only resorting to the more usual slash delimiter iff I need the regex to handle commas. Thus, using commas, I don't have to remember to escape slashes in the regex itself.

Maybe I've been lucky thus far ... AFAIR I've never had occasion to process strings whereby both slashes and commas were of importance :-)

Just my 2 penn'orth...