Jim, I read and enjoyed your book.
Bruin, the rpm range you need power for includes the drop in rpm for the shift lag from 4th to 5th as well as the rpm range you plan to run through in fifth. You also need to include some extra power band width to reflect the sophistication and accuracy of your tune. Add all of this up and it can be 3,000 or 4,000 rpm, even on a five speed bike.
Open ended straight pipes produce the biggest power spike but it is over a narrow band with pronounced lack of horses on each side. They work OK but a person really needs to have a dyno run to know the power curve shape, good info on gearing, the ability to match everything together, and lotsa sprockets. It is much more difficult to make work than it seems.
As mentioned previously, Panic's Victory Papers have some good info. That is what I have lost and cannot find anywhere. He is a forum member. You can make a pipe to his formulae and be close enough.