I'm not sure why a longer tube would cause vacuum leak? I think he doesn't want to install it because of what a PIA it is to get to the PCV valve. Another guy posted 2 threads below you, Kdavis with video of the replacement for PCV, very comprehensive, other thread shows the spark plug replacement. I'd say sit back and watch his videos and see if you can pull any ideas about location for the can. But again, 2 foot, 3 foot, 4 foot...I just don't see that causing any oddity in pressure, and if quality products and installed correctly, no vacuum leaks should occur.