I'm really not a fan of his kits, or any of the others. They are all compromises to make them "bolt-on". But I digress.
1/4" tubing is not nearly enough for a PCV system, not even close. I'm using AN-12, which is 3/4" outside diameter, and I am still not sure if it's big enough, and I'd like to eventually run dual AN-12 lines for the vacuum.
The other problem with your design is that it uses the intake manifold as a vacuum source. Traditionally, N/A motors almost always had vacuum no matter the driving conditions, so it was perfect. However with modern tuning principles, engines rarely have vacuum, as they hold the throttle plate open as much as possible (Vacuum reduces gas mileage). The throttle plate's purpose is to fine tune idle, and to act as a backup in case the computer can't control throttle in other more preferred ways. If you ever go driving ad watch actual throttle percentage, you'll see how it really doesn't follow desired throttle, and that it rarely if ever goes less than 80% open. So, not only will that line rarely ever see any discernable vacuum, but the more troubling part is it will be subject to boost. And even if you have a leak-free check valve, when the motor goes into boost, your PCV and catch can will have zero vacuum, and more troubling, zero flow. And this is when you need adequate flow more than ever. My design isn't close to ideal, I don't have enough valve cover ports (I'd like 4), and I use turbo inlets for my vacuum source. These hardly ever pull any significant vacuum, however they airflow constantly, and that increases with boost.
Ideally, the design pulls a constant vacuum to the catch can, in turn pulling a constant vacuum to the valve cover. However, this requires a vacuum pump, and even on our relatively small engines, the vacuum pump requirement would require a sizable vacuum pump, significantly larger than even the OEM vacuum pump by the HPFP.