I seem to recall from the Cozy list that the work around is just to change hardeners.  I forget whether it was MGS335 fast hardener or the MGS285 fast hardener that had the shipping problem.  The consensus was (your mileage may vary) to just use the hardener from the other MGS system.  They are compatible.

 

I don’t think you can/should mix 335 epoxy with the 287 (Slow) hardener. You may end up with expensive goo and/or a very weak part. I haven’t seen anything that provides for mixing the two systems.