Well, the vid is not there anymore and the topic is close to it's first birthday, but since nobody has replied I will do so.
I have made quite a few pyramid bows and the tillering that you describe is correct and will result in a nice bow. You do want to keep the limb width at the fadeouts (where you start the taper) a bit wide for best effect. Take your tips down to very narrow for best results. The tips can be so narrow that they won't accommodate string grooves on the sides but you can glue a thick overlay on the back of the tip and put a single string groove across the back of it. It's really kinda elegant looking.
The cheap and easy way to build your first one is to get an oak or hickory board at the big box store and make it with that. Look for a board with the grain running straight. If the grain looks like it is straight both on the face and the edge of the board then you have a good one. Don't rush into your board. Shop the lumber department(s) until you find a good one. Don't compromise!
Rather than type out instructions I'm going to give you a link to a build along DIY. Photo bucket wrecked the pictures but you can do it without the pics.