That totally depends on the book and what you're looking for, I think. A text where you're looking for specific answers to things you can probably go thru at 2 sec a page when you don't dip into anything but like you said if there's alot of relevant info who knows how long it will take.
Superreading doesn't have a set time (not that I remember) and the drills were ungodly slow on the tapes but 2-5 sec a page sounds about right. I superread without dipping and then go back thru for skittering/dipping and by then I know EXACTLY where I want to rapid read more and that's it. Rapid reading is tricky, since it's the last step and you've already weeded out the stuff you don't care about you are really reading for comprehension and I wouldn't time yourself.
For that book you're reading I'd let what you need to get out of it deturmine how you PR it. If you have specific Q's guiding you - you can use SuperReading on the whole thing. Or you may have to do it all including Rapid Reading.