Milk jug should work fine. I didn't spring for a waste collector for my PM Hot1, (hang on), I just run a hose down to a plastic bucket with a hole drilled through the top. I usually empty the cup before it starts draining, but glad I had it when I was gone on vacation! 8) I am considering the EV180 for an upgrade, so let me know how you like it.
I use an old 2 gallon water bottle to collect the overflow from my EV 180. I'd hook up a tube to the drain pipe now. The air flowing throught the skimmer carries moisture with it that could condense back into your sump if it's not carried into a separate container. Even that bit of moist air has impurities in it. The water it leaves turns green in the bottle, even before the collection cup starts to overflow!.
These skimmers are great. Easy to clean and they remove some really nasty looking, dark green scum. Enjoy!
I run a waste collector on my EV-180, mainly for the stink control. It's also a decent failsafe when you leave town or just aren't around the tank. Too bad they're so expensive!