There seems to be a raising interest lately for the PLL.
I'd say get your hands on any information you can and study them instead of blindly following Alex's excellent layout. It's a pretty complex build, and you can't really test it before completing it. Even after that, I spend 2 hours trying to decide if it was working properly or not, lol.
As with every big layout, take little and careful steps. The indicator lamp wire coming from the board is actually -12v DC (it seems to buffle everyone that tries to build it), so a normal led wired backwards will do.
I implemented the "drone" and "moment" add-ons, and they work fine, they are just a bunch of connected switches. Here is my drawing of them.
and finally here are some pics of my complete build (I never get tired of showing it off
)
Hope that helps!