Thanks to everyone who replied or sent a private message! My set of graduates arrived today:
I went to a big box store to look at plastic kitchen graduates and they wanted $3 apiece for plastic 1L measuring cups. No thanks, I'll make do with plastic cups. It sounds like as long as I rinse the mixing graduate thoroughly between chemicals I should have no trouble. All the stuff arrives tomorrow and I'll be processing my first roll of Ilford Delta-400. I'll be sure to post the results here!