> When processing large url lists with httrack -%L option
> I seem to run out of filters (according to hts-log.txt)
> What is the drawback in setting -#F to a very high number?> (I'm not sure
what these filters are)

To manage 1,000,000 links, just add (for example, in the 
URL entry or in the filters section) the option:
-#F1000000

Example: you'll have in the Options/Scan rules box:
.. +*.gif +*.jpg -#F1000000