Just pulled my first decoction ever with this brew. For those who are afraid...don't be. I eyeballed the amount to decoct, boiled gently for about 25 mins (during the last 25 mins of my rest at 147), and added it back to the mash. Undershot 160 by a few degrees, but that's what the steam rig is for.
Now, just cross your fingers for me that I don't get a stuck sparge since I couldn't get rice hulls in time for brew day. I'm guessing the barley hulls will create enough of a filter bed - the mash is well mixed.