So I was confused about this as well b/c if you look at the paragraph about propranolol in the latest edition of the Pph (Nov 2019) (I know someone who has access to it), it says 2gm. We didn't know if it stood for 2 grams or if it was a typo for 2mgs (which also wouldn't make sense, too low), b/c usually the abbreviations for grams is (g) or so we thought. Plus, 2 grams SEEMS LIKE an exorbitant amount.
However, on the next page of the book there is a video in which Dr N shows how to mix the SN (which in itself is very informative), and then adds the propranolol saying it is in fact 2 grams, and if you have 40mgs pills like the ones he shows, you need to take 50 of them.
His exact words from the video (see in pics) "..and the way to make your 25grams of SN more powerful is to add 2 grams of propranolol. Given that they are 40 mg tablets, we will need 50 to make it up to 2 grams. " Later he shows he just adds them into the SN mixture. Make sure to strip well to dissolve it all. He also mentions you can get them in other mgs, so obv if you get the 80mgs tablets, you only use 25, yada yada, do the math :)
Its weird to me that in the video he only adds a few of the propranolol tablets, not 50 like he says you should, but I guess he doesn't have that many, and just showing HOW to add them is enough for an instructional video. TO ME THOUGH, it really seems like 2gs is an overkill if you compare it to the average doses which are like 80-300ish mgs/day depending on condition. But what do I know, I'm not the man helping people die peacefully :)