I am confused by your post. Do you mean to say that you usually carb by shaking, and this time you want to carb without shaking? You can use this table to figure out your set-it-and-forget-it pressure, and you'll be done in a week or two.
Oh ok. I didn't know it took that long. I will just shake it. I usually go with 30 lbs for ten minutes. Do you think that's suitable for a brown ale?
It's impossible to say. It depends entirely on temperature and rate of dissolution. There are other methods of carbing that go quicker. Look up burst carbing if you're interested. Otherwise, keep shaking.