Some shakes like Isopure(I believe 1 carb) and ON 100% Gold Standard(3-4 carbs) are fine, because they have such a low amount of carbs. You obviously don't want to drink them like water, because the carbs add up perty fast
Somewhere in this thread(I think the 3rd or 4th page) has a doc that is REALLY helpful, it's a spreadsheet. Just stick in your BF% and weight, and it gives you your macros, even for carb up
For carbs, you generally try to stay below 20, excluding fiber. With the fiber, I have heard of people getting up to 50, but I personally try not to get over 30-35, fiber included. Also grabbing some ketostix help some, but the amount of water screws it up too, so it is just to give you an idea of what knocks you outta keto and crap.
There's also a list of food in I think this thread that is pretty helpful
EDIT: Also, try to have protein after your workout, then the fat/meal about an hour later. Fat + protein = slower digestion of protein. Atleast from what I know ^_^
And also, do you have your workout(s) setup? The weekday workouts should be normal, and then the Friday night one a depletion. And you should start the carb load RIGHT after your workout, not an hour or two later. I can't remember the specifics, but you lose out on something, lol, maybe Thomas can explain it