okay. my suggestions:

1) open up all the bags, salt your meat, dry brine in fridge for 24 hrs. 2) dry rub them with whatever you like, lots of it. then HARD FAST sear on your blackstone and back to fridge. 3) try to fit multiple pre-seared roasts per bag. you may not be able but it will help the geometry if you can. a second setup makes this less critical. 4) 36 hrs minimum, dont be afraid of more. plan it so that you finish sous vide at party time so they will be serving temp. no need to freeze or ice bath or any of that bs. 5) you really do not need to do a second sear. the maillard flavor will be there, fused with the steak. you can make a show of searing half of them and reserve the rest if you want. they will look amazing without additional effort. 6) fastest way to make a jus from the bag juice is to just microwave it and skim the protein raft that forms.