For what it's worth, I cut the large flat-iron muscle across the grain, and did not worry about the connective tissue that runs down the middle of the steak. I could have cut that out, but the steaks were already relatively small, and cutting them in half would have made them worse.
Had I realized that the Jaccard was going to flatten them so much, I would have cut them much thicker -- perhaps 2" or so. Next time.
The first attempt at 12 hours was definitely "blah" in both taste and texture.
Tonight, I served another batch cooked for 24 hours. These were better, but still not a home run. They were still a little dry, and any fat on the edges was relatively tough -- almost surprisingly so. Maybe I need to use the blow torch, rather than the hot skillet to sear the meat.
Another package is in the rice cooker tonight, still at 131F/55C, in order to try 48 hours -- the way I have done brisket very successfully. Since the brisket is from a close neighbor of the flat-iron, I hope it will work as well.
One question that I have concerns the au jus that is poured off of the steak. It is rather red, presumably indicating some blood. I've tried adding a little wine, with or without some flour, to make a quick gravy, but the results are an unappetizing gray, and not particularly flavorful.
Any suggestions from anyone?
MikeTMD, I will put the Stampfer book on my list, after the Joan Roca book arrives, and after I order the Fat Duck cookbook. How good is the translation? Although I can read and perhaps speak German from 50 years ago, I'm certainly not fluent.
Try filtering your liquid from the bag to get rid of the protein which when heated will turn into scum and it is not very appealing. After filtration, you will have a much better medium to make your au jus or gravy.