IIRC, there are versions of xargs that call the program multiple times with "chunks" of input if a single command line is too big. Whether this is good for you depends entirely on the application you're writing.

In this case, anyway, I don't fully get the rationale to use find ... | xargs ... when one can make my_script.pl read filenames directly from standard input. Moreover, setting $/ = "\x00" should do the trick to tandem with find -print0.