Dupont has applications engineers available to help with this and will be happy to send you out some compatibility guides. The literature I have shows the Viton busuness center phone number as 410 392 2500, or Toll-Free at 800 853 5515
My experience with Viton is that is is highly chemical resistant, except it is not happy with chemicals bearing acetate radicals, amines, and it swells a little in water.
There are a LOT of Viton recipes available even from DuPont, and there is probably an optimal formulation for your HFE-71IPA stuff.