There is no reason why you cannot activate a book in one day so 2 or 3 days is perfectly okay too.
What to do?
Apply the 5 day step doing day 2 and 3 exercises the same day. If you can PhotoRead the book and let it incubate over night or at least 20 minutes. The first day has the shortest exercise. Do day 2 in exercise in the morning and day 3 in the afternoon. Here again we are allowing the book to incubate further as well as mind probing questions. Day 4 you do the following morning and day 5 in the afternoon. In effect you will be able to complete a book in 3 days.
Like I said the reason for a break between activation is to allow you to incubate the book more. This helps you to gain even better comprehension than if you just read the book through. It also helps with the long term memory.
Alex